The question misses the entire point of the event. God did slay His Son for the salvation of humanity. The entire episode was to play out this scenario, that humanity might better understand what was being done for them by God the Father, through Jesus Christ His Son. It was the weight of our sins that killed our Lord and Savior Jesus Christ. Those sins did not just naturally fall upon the Holy One, who knew no sin, they were placed upon Him by the only One who could do such a thing.
Nevertheless, death could not hold the Holy One in the grave because He took our sins upon Himself for our salvation, but knew no sin Himself. He laid down His life, and He took it back again. This is our salvation. No one but God could have accomplished such for fallen humanity. Abraham represented God the Father who must sacrifice His Son, and Isaac represented God the Son who willingly laid down His life by faith in the father for fallen humanity. Thus leading the way as a man, for the rest of humanity to follow. God never intended to actually allow Abraham to sacrifice Isaac, the whole event was a lesson on the cost of the salvation of humanity.
Mat 10:38 And he that taketh not his cross, and followeth after me, is not worthy of me. 39 He that findeth his life shall lose it: and he that loseth his life for my sake shall find it.
Mat 16:24 Then said Jesus unto his disciples, If any man will come after me, let him deny himself, and take up his cross, and follow me. 25 For whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it. 26 For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul?
Rom 6:1 What shall we say then? Shall we continue in sin, that grace may abound? 2 God forbid. How shall we, that are dead to sin, live any longer therein? 3 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death? 4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life. 5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection: 6 Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin. 7 For he that is dead is freed from sin. 8 Now if we be dead with Christ, we believe that we shall also live with him: 9 Knowing that Christ being raised from the dead dieth no more; death hath no more dominion over him. 10 For in that he died, he died unto sin once: but in that he liveth, he liveth unto God. 11 Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord.
Rom 8:1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit. 2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death. 3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: 4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit. 5 For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit. 6 For to be carnally minded is death; but to be spiritually minded is life and peace. 7 Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be. 8 So then they that are in the flesh cannot please God.
Gal 2:20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.
Jesus became a man and died for humanity, that humanity might be empowered to follow His lead and example. Will we sacrifice the old man by faith in Jesus Christ who leads the way, or not. Jesus took fallen humanity upon Himself, and lead it to the cross where it died under the penalty of the law, when He came forth from the grave He left fallen humanity within it. Now those who by faith enter into this experience with their Lord and Savior Jesus Christ, choose to leave fallen humanity in the grave as well. Which event will be literal and once and for all for each individual saved in Christ at His coming. Till then it is a spiritual experience by faith in Christ Jesus our Lord.
1Co 15:50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption. 51 Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed, 52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed. 53 For this corruptible must put on incorruption, and this mortal must put on immortality. 54 So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory. 55 O death, where is thy sting? O grave, where is thy victory? 56 The sting of death is sin; and the strength of sin is the law. 57 But thanks be to God, which giveth us the victory through our Lord Jesus Christ. 58 Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.