Since I believe that the Doctrine of Penal Substitution is of primary importance, I think it may be helpful to discuss the Biblical basis for it. I want to introduce one text, discuss it, and then move on. I believe that P.S. is found in several places in Genesis, but I think it is probably simpler to start in Exodus: Exodus 12. The Passover. In the first nine plagues, disaster falls only upon the Egyptians, but in the tenth, it will fall also upon the Israelites unless they take certain precautions. A lamb must be slaughtered, and its blood applied to the door frame of every house. The clear implication is that unless this is done, the first-born child will die in every house that is not covered by the blood. V.13. 'When I see the blood, I will pass over you.' Implication: "If I don't see the blood, I won't pass over you." Thus the lamb becomes a substitute for the firstborn son, dying in his place. This applied to every single house of the Israelites. If one house neglected to perform the rite, the fact that the neighbours had done it wouldn't help. A particular lamb died for a particular child. The blood was to be applied to the doorposts with a sprig of hyssop (v.22). So when David, in the midst of his sins, cries, "Wash me with hyssop and I shall be clean" (Psalm 51:7), he is pleading that the blood of the Passover lamb be applied to him also. The Holy Spirit also tells us today that 'Indeed Christ, our Passover, was sacrificed for us' (1 Cor. 5:7). Christ's blood was shed for those hearts are sprinkled with the blood of the Passover Lamb (Heb. 9:19-22; 10:19-22). It might be asked, what were the sins for which the Israelites needed atonement? Ezek. 20:4-10 tells us that they had shared in worshipping the false Egyptian gods. Thus we are particularly told that the plague on the firstborn is 'Judgement on all the gods of Egypt' (Exod. 12:12). That's very brief, but I hope it's reasonably clear. Please comment and then we can move on to the next text.