Defendant contends that the trial court committed prejudicial error in admitting the testimony of Lieutenant Daniel Qualls, a detective with the Alamance County Sheriff’s Department. The essence of defendant’s contention is that the officer was able to testify in a narrative fashion as to his interpretation of the events which occurred on the evening of 24 December 1977. By so doing, he was then able to fill in portions of the narrative which were crucial to the state’s case but which had not been testified to by any of the state’s witnesses. Defendant therefore concludes that the testimony of the detective was not corroborative in nature but was, in fact, incompetent hearsay whose admission entitles him to a new trial. We disagree.
During the presentation of the state’s case-in-chief, Robert Moore testified on direct examination that
[Defendant] went around the car from the front of it and opened the door and pulled this guy out. There were no lights except the headlights. . . . Well, he — he—he pulled him out and went to the bridge with him. I heard Charlie [Phillips] say, ‘Man,’ say, ‘don’t throw that boy in that cold-ass water,’ and about this time I heard the water splash. ... I heard the water splash and just continued sitting in the car. I didn’t hear anybody say anything except Charlie. As to what happened outside the car, it was sort of a blur like and dark outside the car. I saw him when he pulled the Yancey boy out of the car onto the bridge with him.
Later on in the state’s case-in-chief, Detective Qualls testified regarding a conversation he had with Robert Moore on 12 January 1978. On direct examination, the officer testified that Moore told him that
. . . the defendant, Wilbert Rogers, gets out, goes around in front of the vehicle, opens the passenger’s door on the car, takes the defendant — correction, takes the victim, Talmadge Yancey, out, takes him over to the side of the bridge and throws him over. He heard the man hit the water, hears the splash. From the time he heard the — heard the splash, he didn’t hear any more struggling, no more splashing in the water.
*601Corroborative testimony is testimony which tends to strengthen, confirm, or make more certain the testimony of another witness. See State v. Case, 253 N.C. 130, 116 S.E. 2d 429 (1960), cert. denied, 365 U.S. 830 (1961); Lassiter v. Seaboard Air Line Ry., 171 N.C. 283, 88 S.E. 335 (1916). Where testimony which is offered to corroborate the testimony of another witness does so substantially, it is not rendered incompetent by the fact that there is some variation. State v. Lester, 294 N.C. 220, 240 S.E. 2d 391 (1978); State v. Westbrook, 279 N.C. 18, 181 S.E. 2d 572 (1971), death sentence vacated, 408 U.S. 939 (1972). It is the responsibility of the jury to decide if the proffered testimony does, in fact, corroborate the testimony of another witness. State v. Lester, supra; State v. Case, supra.
A careful comparison of the testimony of the detective with that offered by the witness Moore indicates that the two are substantially the same account of the activities which occurred on the Stoney Creek Bridge on the evening of 24 December 1977. This same analysis clearly shows that the testimony of Detective Qualls goes beyond that of Moore in one important respect: At no time did Moore testify that he actually saw defendant throw Talmadge Yancey over the side of the bridge. However, the clear implication of Moore’s testimony is that defendant did precisely that act. That Moore did not mention one act which was clearly a component of a series of interrelated acts does not in any way serve to abridge the probative force of the rest of his testimony.
That the testimony of the detective differed from that of Moore in that it embodied an additional element in its narrative of the events of 24 December 1977 does not render it incompetent as corroborative evidence. We do not mean to suggest that we are calling into question the continued viability of the rule of State v. Brooks, 260 N.C. 186, 132 S.E. 2d 354 (1963). Brooks stands for the proposition that the state may not introduce new evidence through testimony which purportedly corroborates the testimony of a prior witness. On the facts of this case, Brooks does not come into play in that the proffered testimony meets the threshold test of substantial similarity. It must be observed also that in the present case, there was no objection to this portion of the officer’s testimony, nor was there a motion to strike. Had there been such a request, the court would have been obligated to instruct the jury that the officer’s testimony was not substantive *602evidence but was to be considered by them with reference to the weight and credit they would give to Moore’s testimony if the jury found that it did corroborate his testimony. See State v. Westbrook, supra. There was no error.
At a later point in his direct examination, Detective Qualls testified with respect to a trip to the Stoney Creek Bridge with Moore in early March 1978. Over objection, the officer testified about what Moore told him on the trip as to where defendant had stopped the car on the bridge on the evening of 24 December 1977 and Moore’s pointing out where the car stopped. We perceive no error in the admission of this evidence as it too was competent to corroborate Moore’s testimony. State v. Westbrook, supra; see generally 1 Stansbury’s North Carolina Evidence §§ 50, 52 (Brandis Rev. 1973).
 Defendant assigns as error the following portion of Judge McLelland’s charge to the jury:
If the State does not prove beyond a reasonable doubt that the defendant did not act in the heat of passion upon adequate provocation and that his action was so soon after the provocation that the passion of a person of average mind and disposition would not have cooled, then you may not find the defendant guilty of second-degree murder, but he would at most be guilty of voluntary manslaughter.
Defendant argues that the quoted instruction was erroneous and prejudicial to him. The state argues that even if the instruction was erroneous, it was favorable to defendant because it placed a greater burden on the state than is required. The state further argues that any error in the instruction was cured by later instructions given by the court.
Reasonable minds can disagree as to the true meaning of the instruction complained of. We can appreciate the difficulty the trial judge encountered in charging juries in compliance with the decision in Mullaney v. Wilbur, 421 U.S. 684, 44 L.Ed. 2d 508, 95 S.Ct. 1881 (1975), which mandated our decision in State v. Hankerson, 288 N.C. 632, 220 S.E. 2d 575 (1975), rev’d. on other grounds 432 U.S. 233, 53 L.Ed. 2d 306 (1977). Nevertheless, we must say that the challenged instruction is confusing and difficult, if not impossible, to understand.
*603Assuming, arguendo, that the instruction is erroneous, we hold that it was not prejudicial to defendant in view of the later instructions given by the trial judge.
Second-degree murder is the unlawful killing of a human being with malice, but without premeditation and deliberation. State v. Cousins, 289 N.C. 540, 223 S.E. 2d 338 (1976); State v. Duboise, 279 N.C. 73, 181 S.E. 2d 393 (1971). Voluntary manslaughter is the unlawful killing of a human being, without malice, express or implied, and without premeditation and deliberation. State v. Rummage, 280 N.C. 51, 185 S.E. 2d 221 (1971).
After the jury had retired to commence its deliberations, they returned to the courtroom and, through their foreman, requested additional instructions on the crimes of second-degree murder and voluntary manslaughter. In his supplemental instructions, Judge McLelland stated that:
Mr. Foreman and members of the jury, as indicated in the instructions yesterday, second degree murder is defined in law as the intentional, unlawful killing of a human being with malice. The State, to prove second degree murder, must prove that the act which proximately caused the death was intentional. It is not required to prove that the defendant had a specific intent to kill, but specifically intended to do the act which proximately caused the death. The killing of a human being is unlawful unless excused by some circumstances, and I instruct you that there are no circumstances in evidence which would excuse the killing.
The State, to prove second degree murder, must prove by evidence beyond a reasonable doubt that two things, first, that the defendant intentionally and without malice pushed Ray Yancey over a bridge. Malice is hatred, ill will, or spite and is also that condition of mind which prompts a person to take the life of another person by an intentional act which proximately results in the death of that other person without just cause or excuse or wantonly to act in such a manner as to manifest depravity of mind, a heart devoid of a sense of social duty and a callous disregard for human life. And secondly, the State must prove beyond a reasonable doubt that the act of pushing Ray Yancey off the bridge was a prox*604imate cause of Yancey’s death. Proximate cause is real cause, cause without which Yancey would not have died.
Voluntary manslaughter is the unlawful, intentional killing of a human being without malice. Unlawful is, as I have defined if (sic) before, a killing not justified by any excuse the law recognizes; and I instruct you again there is no evidence of any excuse in this case that the law recognizes as justifying the killing. The intentional aspect again is not a specific intent to kill, but an intent to throw him off the bridge. The State must prove beyond a reasonable doubt that that act was intentional. The State need not prove that he acted with malice. If, however, the State has proved that he acted with malice, then you must consider whether or not the evidence shows, not beyond a reasonable doubt but simply shows, that he acted in the heat of passion, or heat of blood, upon adequate provocation. . . .
If he acted in the heat of passion, or heat of blood, upon adequate provocation though you find there was malice, not considering the action in the heat of passion, then he would be guilty at most of voluntary manslaughter, not second degree murder, for one who acts in the heat of passion acts without malice; and though you find other evidence of malice, if you find, if you believe, the State’s duty being to prove beyond a reasonable doubt that he did not act in the heat of passion, if you believe he acted in the heat of passion, then he can be guilty of no higher offense than manslaughter, voluntary manslaughter.
So I instruct you as to voluntary manslaughter, as I instructed you yesterday, that if you find from the evidence beyond a reasonable doubt that on or about December 24-25, 1977, the defendant intentionally pushed Ray Yancey over the bridge, but the State has failed to satisfy you that in doing so he acted with malice either in that the State’s evidence does not prove beyond a reasonable doubt that he had malice toward Yancey or the State has not proved beyond a reasonable doubt that he did not act in the heat of *605passion upon adequate provocation; and if the State has further proved beyond a reasonable doubt that the defendant’s act was a proximate cause of his death, your duty would be to return a verdict that he is guilty of voluntary manslaughter.
These further instructions stated accurately the applicable rules of law as we have summarized them above. That the jury requested additional instructions indicates that they might have been confused by the earlier instructions.
The charge of the court must be construed contextually, and isolated portions will not be held prejudicial error when the charge as a whole is free from objection. E.g., State v. Bailey, 280 N.C. 264, 185 S.E. 2d 683, cert. denied, 409 U.S. 948 (1972). The supplemental instructions of Judge McLelland, when coupled with the principal instructions he first gave, correctly informed the jury as to the applicable law and in no way prejudiced defendant’s rights to a fair trial.
The decision of the Court of Appeals is