If there is one passage in the whole of Scripture that contains the doctrine of penal substitution in its most clear form, it is Isaiah 53. Here, truly, we stand on holy ground! Those who criticize the traditional view of the atonement must become contortionists to escape the implications of this passage. Some claim this is not referring to Jesus at all, and yet Jesus Himself and many of the New Testament writers clearly apply this passage to Him. For example, this is the passage which the Ethiopian eunuch was reading, and which Philip used to explain the Gospel to him clearly applying what the prophet had to say in Isaiah 53 to Jesus. (Acts 8)

In Isaiah's prophecy we see that Jesus takes on Himself our sins, griefs, and sorrows. We see clearly that He is ACTIVELY punished by God with words like smitten, afflicted, wounded, chastised, and crushed all being attributed to God. We see that it was Jesus’ suffering that made our salvation possible. What more do we need to convince us? I will simply let the passage speak for itself:

“Surely he has borne our griefs and carried our sorrows; yet we esteemed him stricken, smitten by God, and afflicted. But he was wounded for our transgressions; he was crushed for our iniquities; upon him was the chastisement that brought us peace, and with his stripes we are healed. All we like sheep have gone astray; we have turned every one to his own way; and the Lord has laid on him the iniquity of us all … it was the will of the Lord to crush him; he has put him to grief; when his soul makes an offering for sin … out of the anguish of his soul he shall see and be satisfied; by his knowledge shall the righteous one, my servant, make many to be accounted righteous, and he shall bear their iniquities … he poured out his soul to death and was numbered with the transgressors; yet he bore the sin of many, and makes intercession for the transgressors.” (Isaiah 53:4-12)