You are right in saying that only Matthew, Mark, and Luke mention Simon of Cyrene carrying the Lord’s cross for Him.  Let’s read this sad account in Matthew 27:27-32, “Then the soldiers of the governor took Jesus into the common hall, and gathered unto him the whole band of soldiers. And they stripped him, and put on him a scarlet robe. And when they had platted a crown of thorns, they put it upon his head, and a reed in his right hand: and they bowed the knee before him, and mocked him, saying, Hail, King of the Jews! And they spit upon him, and took the reed, and smote him on the head. And after that they had mocked him, they took the robe off from him, and put his own raiment on him, and led him away to crucify him. And as they came out, they found a man of Cyrene, Simon by name: him they compelled to bear his cross.” 

We know very little about Simon.  He was from Cyrene (present day Libya.)  He had two sons named Alexander and Rufus (Mark 15:21).  Simon was compelled, or forced, to carry the Lord’s cross (Matthew 27:32). Simon walked behind the Lord Jesus as he carried His cross (Luke 23:26).  It is largely assumed that because Simon was in Jerusalem at this time, he was there to observe the Passover.  After this incident, we do not read of Simon again. 

Why would Simon need to carry the Lord’s cross?  It was customary that the person being crucified would carry his own cross out to Golgotha, there to agonize for days until death finally took him.   We are told in all four Gospels that the Lord Jesus was scourged (Matthew 27:26, Mark 15:15, Luke 23:22-24, John 19:1).  While it was customary to scourge (beat with a whip) those who were about to be crucified, it seems the Lord’s beating was very extreme.  We read prophetically of the Lord Jesus in Psalm 129:3, “The plowers plowed upon my back: THEY MADE LONG THEIR FURROWS.”  We also read of Christ in Isaiah 52:14 where it says, “As many were astonied at thee; his visage was so marred more than any man, and his form more than the sons of men.”  How terribly He was beat…so much so that He did not even look like a man anymore. 

It is easy to see why the Lord could not bear His cross all the way to Calvary.  Let’s look at Matthew 27:32 again, “And AS THEY CAME OUT, they found a man of Cyrene, Simon by name: him they compelled to bear his cross.”  This seems to show us that the Lord Jesus bore His cross until He passed through the walls of the city.  Perhaps He stumbled under the weight of the cross with the extreme beatings compounding His physical weakness.  At one point, the soldiers decided to grab Simon and make him carry the Lord’s cross behind him.

Now, John 19:16-18 tells us, “Then delivered he him therefore unto them to be crucified. And they took Jesus, and led him away. And he bearing his cross went forth into a place called the place of a skull, which is called in the Hebrew Golgotha: Where they crucified him, and two other with him, on either side one, and Jesus in the midst.”

John states that Jesus “went forth” bearing His own cross. That simply means He started the walk to Golgotha carrying His cross. Matthew, Mark, and Luke mention that the Roman guards demanded Simon to bear the Lord’s cross. What obviously happened was, Jesus started to carry the cross, was unable to because of the severe beating, and Simon was pulled out of the crowd by the Romans and forced to carry the cross.

However, John does not mention Simon. Why? Because John’s gospel is not about who carried the cross, nor how Jesus got to Calvary. John is focused on the crucifixion itself. He simply writes that Jesus started out by carrying His own cross, which is true. On the other hand, the other gospels give us more details about the Lord going to Calvary.  It is when we compare all four of the Gospels that we get a complete picture of what happened on this day of the Lord’s crucifixion.  (CC)  (541.4)