delivered the opinion of the court:
This is an appeal from a decision of the Appellate Court of Illinois, First District, reversing a decree of the superior court of Cook County modifying a child custody award, and remanding the cause.
Defendant, Herbert Nye, appellant here, and plaintiffappellee, formerly Constance Nye and now Mrs. Herbert Bruckner, were married on April 10, 1938. One child, a daughter, Diane, known as Penny, was born to the parties on October 1, 1942. Plaintiff filed suit for divorce from defendant in the superior court of Cook County on November 15, 1948, on the ground of desertion. On December 21, 1948, the court entered a decree granting plaintiff a divorce on the ground that defendant “wilfully deserted and absented himself from the plaintiff, without any reasonable cause or provocation, for the space of over one year immediately prior to the filing of this suit, and still persists in such desertion.” The decree also recites that the par*411ties, represented and advised by their respective attorneys, freely and voluntarily entered into an agreement in writing, settling between themselves the custody and support of the child. The decree recited that it was for the best interests of the child that her custody be divided in accordance with that agreement. This agreement provided that the care, control, and custody of the child shall alternate, yearly, between the parties, with reasonable visitation privileges on week ends and holidays to the other party. Possession of a described home was to vest in the one then in custody of the child. Under this agreement plaintiff had custody of the child during the first year.
During the early morning hours of February 25, 1949, the defendant carried the child away from the plaintiff’s custody without permission and contrary to the provisions of the divorce decree. Plaintiff on March 8, 1949, filed a petition praying the divorce decree be modified to allow her the decreed custody of the child without living in the specified house, that defendant be required to surrender the child to her, and that a rule be entered on defendant requiring him to show cause why he should not be punished for contempt of court for his seizure of the child contrary to the provisions of the divorce decree. Defendant entered an answer and a counterpetition praying the decree of divorce be modified so as to award him the sole care, custody, control, and education of the child, depriving plaintiff of all visitation privileges, and such other relief as seems just and equitable. Defendant alleged he entered the home occupied by plaintiff and the child at approximately 2:30 A.M., on February 25, 1949, and found plaintiff engaged in improper conduct with Herbert Bruckner, who was not then her husband, but who became such that afternoon. He alleged the marriage was consummated for the purpose of attempting to overcome the immoral act of that morning, that plaintiff and Bruckner committed such act in the home where she and the child resided, and *412at other times had conducted themselves in an immoral manner, that the plaintiff had committed adultery many times with Bruckner and one J. B., and that plaintiff was unfit to have custody of the child at any time.
After several hearings on the pending issues, the custody provisions of the divorce decree were modified. Plaintiff was found unfit to have custody of the child, Penny, and permanent custody was awarded to defendant, the plaintiff to have custody during vacation period from July 1 to August 15 of each year. The chancellor stated in his opinion that since the decree for divorce the circumstances of the parties had materially changed, and, hence, custody should be changed in the best interests of the child’s welfare.
Plaintiff then prosecuted an appeal to the Appellate Court. The chancellor entered an order refusing to make the appeal act as a supersedeas. That order was reversed and supersedeas allowed. Nye v. Nye, 342 Ill. App. 11.
The Appellate Court stated that evidence of the conduct of the plaintiff previous to the decree, not bearing on the alleged misconduct of Bruckner and the plaintiff in February, 1949, was .not admissible on the question of change of circumstances, and that the divorce decree established plaintiff’s fitness for custody at that time. Defendant was at that time satisfied as to plaintiff’s fitness. Assuming the defense testimony of events prior to and after the divorce is true, the court found no change in the relationship of plaintiff and Bruckner between the decree and their marriage. There was no condition attached to plaintiff’s custody rights, and no condition was broken by the alleged misconduct of plaintiff. There is no showing of unfitness on the ground of plaintiff’s lack of care of Penny since the decree. The plaintiff’s misconduct with Bruckner does not disqualify her as custodian of the child, nor is there any justifiable inference of promiscuity on her part. There is no evidence the child ever witnessed any misconduct on the plaintiff’s part. Assuming the chancellor decided the *413factual issues correctly, the court found the judgment of unfitness to be wrong as a matter of law. Finding no unfitness nor change of circumstances, the Appellate Court held that the modification of the decree giving sole custody to the defendant was an abuse of discretion. Accordingly, the Appellate Court reversed the modification decree and remanded the case for further proceedings not inconsistent with its opinion.
Defendant here prosecutes this appeal alleging the Appellate Court erred in reversing the modification decree by holding that the chancellor abused his discretion, that the chancellor’s finding that plaintiff was an unfit person to have custody of the child as a matter of law was wrong, and that the evidence of plaintiff’s misconduct prior to the decree of divorce was inadmissible because the modifying decree recited a change of circumstances subsequent to the divorce.
Plaintiff, in answering, first claimed this court was without jurisdiction to hear this appeal, as the judgment of the Appellate Court was not a final judgment as required by section 75 of the Civil Practice Act. It is a familiar rule that the question of the lack of jurisdiction of a court to entertain a particular case may be raised at any time during the proceedings in that court. Town of Kingston v. Anderson, 300 Ill. 577.
The words of the Appellate Court that the cause is remanded for “further proceedings not inconsistent with this opinion” are of no significance in determining what course should be pursued by the trial court. After a judgment is reversed and the cause is remanded the inferior tribunal can take only such further proceedings as conform to the judgment of the appellate tribunal. It is not required that specific directions shall be stated in an order reversing a judgment and remanding a cause, and it is the duty of the court to which the cause is remanded to examine the opinion and proceed in conformity with the *414views expressed in it. It is the rule that where a court of appellate jurisdiction, in considering a cause, determines the issues and decides the questions involved upon their merits, and the judgment is reversed and the cause remanded with directions to proceed in conformity with the views expressed in the opinion, there is no power in the court below except to enter a final order or judgment without retrial. (Roggenbuck v. Breuhaus, 330 Ill. 294.) Here, the Appellate Court determined the issue and decided the question of custody on the merits. Thus, as to the custody, the trial court has no power but to issue a final order or decree. In such a case the judgment of the Appellate Court is final and subject to further review by this court. Wenham v. International Packing Co. 213 Ill. 397; Roggenbuck v. Breuhaus, 330 Ill. 294.
Under our divorce statute the court is clothed with a large discretion in determining to which parent a child will be given. It is usual in such cases, due to the tender years of the child and in consideration of its best interests, to entrust its care and custody to the mother, she being a fit and proper person to rear the child. (Miner v. Miner, 11 Ill. 43; Draper v. Draper, 68 Ill. 17.) The maternal affection is more active and better adapted to the care of the child. Especially is this true in the case of a minor daughter, where the care and guidance of a mother’s hand is doubly important. This principle has become so well fixed and followed in this State that this court has not in recent years been called to rule upon it. Therefore, compelling evidence must be presented, proving the mother to be an unfit person, to cause the custody of her minor daughter to be denied her, or there must be a positive showing that to deny custody to the mother would be for the best interests of the child.
People v. Hickey, 86 Ill. App. 20, takes the above principle and applies it to a circumstance even more appalling than that alleged here. In that case the custody of a minor *415daughter was left with the mother even though the decree of divorce was allowed because of the adultery of the mother, she having lived as husband and wife with another man prior to the divorce. The court focused its attention primarily on the welfare of the child, and based its determination on the fact that the mother had married her paramour, no other indiscretions were shown, and she now led a respected life in a good community with her now husband. The court found nothing which would be detrimental to the best interests of the child, but rather found her welfare dictated the custody of the mother. This same principle has been applied in other cases in this State, and this specific case has been followed in many other jurisdictions. The prior misconduct gave no evidence of adverse effect on the future welfare of the child. Where the mother is able to care for her minor daughter and is not shown to lack the proper attributes of good motherhood, past misconduct, where the evidence indicates no probable future misconduct, should not be a basis for denying custody to the mother. To do so would be not only to punish the mother for her past misconduct, but, more important, would punish the child by denying her a mother’s care and guidance. It is not the purpose of this court, nor of any court, to so punish an innocent child. The guiding star is and must be, at all times, the best interest of the child. Other than the alleged prior misconduct on the wife’s part here, she is shown to be an affectionate, dutiful mother, giving proper care and guidance to her child. She is married to the only man with whom she allegedly was indiscreet. She has a good home and is respected in her community. She has never been absolutely proved to be an adultress, nor was any of the alleged misconduct absolutely proved. No different conduct has allegedly occurred that the husband does not declare he was generally aware of at the time of the decree. At that time he voluntarily entered into a custody agreement which accepted her as a fit person. The *416decree of the court accepted her as a fit person. The Appellate Court was, therefore, correct in its determination of fitness.
It is true that the chancellor is given a large discretion in awarding custody of minor children. However, such discretion is a judicial one and not unlimited. It is subject to review. Cohn v. Scott, 231 Ill. 556.
After a divorce decree in this State the custody of the children is always subject to the order of the court which enters the decreé and may be changed from time to time as the best interests of the children demand. The decree is res judicata as to the facts which existed at the time it was entered but not as to facts arising thereafter. (People ex rel. Stockham v. Schaedel, 340 Ill. 560.) In proceedings involving child custody the order of the court or judge having competent jurisdiction is a final order, and is binding upon the parties under the same facts and so long as the same conditions exist as did at the time of the hearing and order. (Cormack v. Marshall, 211 Ill. 519.) New conditions must have arisen to warrant the court changing its prior custody determination, (Stafford v. Stafford, 299 Ill. 438,) where the court was not imposed on by perjury or collusion of the parties. The trial court, here, in entering its modification decree, relied on changed conditions. Assuming defendant’s allegations are true, there is no showing here of change in conditions warranting a modification of the custody decree. The defendant’s testimony of the relationship of plaintiff and Bruckner shows no change between the decree and their marriage. There is no change in condition that adversely affects the best interests of Penny.
The determination of the Appellate Court was correct on all points of law. There was no change of conditions as required by law, there was no proper determination of unfitness on plaintiff’s part, and the modification decree was thus an abuse of discretion by the chancellor. This *417judgment, however, is binding only in relation to the case here presented, and effects no prejudice to defendant’s right to question the propriety of the custody decree should grounds therefor arise hereafter.
The judgment of the Appellate Court is affirmed in all respects.
, Judgment affirmed.