“he must.” Jesus’ statement contains three imperative verbs: “deny,” “take up” [lift up], and “follow.” In some cases, the imperative verb has the sense of an invitation, hence the traditional translation, “let him.” In this context, however, the sense of the verse is not an invitation, but a command, and a number of versions pick up on that fact (cp. HCSB; NAB; NET; NIV; and The Source New Testament).
“take up his cross.” To take up one’s cross” is to be willing to do what is right for the sake of Christ even if you do not want to (like Christ in Gethsemane who did not want to be crucified), and also to suffer for Christ if doing the will of God means suffering (1 Pet. 3:17; 4:9. Cp. Phil. 1:29). Carrying one’s own cross is mentioned several times in the Gospels (Matt. 16:24; Mark 8:34; Luke 9:23; 14:27).
The phrase “take up one’s cross” comes from the Roman custom of crucifixion and the fact that it often occurred that the person about to be crucified had to carry his own cross or a piece of it, just as Jesus and then Simon had to carry the cross-piece of Jesus’ cross (John 19:16-17; Matt. 27:31-32). Although the custom of crucifixion was Roman, the dominance of Rome at the time of Christ was such that the whole Mediterranean world and the Middle East was familiar with it, and thus understood what Jesus said when he said that anyone who followed him must take up their cross.
Sadly, the term “taking up one’s cross” or “bearing one’s cross” has been misunderstood and misused in Christendom. It does not refer to “suffering” in general. The wicked suffer for many reasons, but they do not suffer for the cross. Furthermore, much of the suffering righteous people endure is not related to following Jesus.
Jesus was not speaking of the fact that everyone suffers, he was specifically referring to the fact that godly people who openly follow him will suffer (cp. 2 Tim. 3:12). Jesus knew that the Devil has so orchestrated life that people who live godly lives will suffer, and it is not right or godly for a disciple of Christ to act like the people of the world act and thus try to avoid the suffering that comes with being a follower of Christ. Jesus said, “he must deny himself and take up his cross and follow me.” The true disciple “must” be willing to suffer for Christ, as difficult as that suffering can be.
[For more on the transfer of the cross from Jesus to Simon, see commentary on John 19:17. For more on the chronology of the events of the last week of Jesus’ life, see commentary on John 18:13].