In order to understand Matthew 16:26, we have to put it into context of the words around it. Here is the rest of the passage: “21 From that time on Jesus began to explain to his disciples that he must go to Jerusalem and suffer many things at the hands of the elders, the chief priests and the teachers of the law, and that he must be killed and on the third day be raised to life. 22 Peter took him aside and began to rebuke him. ‘Never, Lord!’ he said. ‘This shall never happen to you!’ 23 Jesus turned and said to Peter, ‘Get behind me, Satan! You are a stumbling-block to me; you do not have in mind the concerns of God, but merely human concerns.’ 24 Then Jesus said to his disciples, ‘Whoever wants to be my disciple must deny themselves and take up their cross and follow me. 25 For whoever wants to save their life will lose it, but whoever loses their life for me will find it. 26 What good will it be for someone to gain the whole world, yet forfeit their soul? Or what can anyone give in exchange for their soul? 27 For the Son of Man is going to come in his Father’s glory with his angels, and then he will reward each person according to what they have done” Matthew 16:21-27

Jesus is explaining to his disciples the nature of what he came to do. That he must suffer, die and be raised to life on the third day. Peter doesn’t understand this, he thinks that if Jesus really is the Messiah He shouldn’t have to suffer. He thinks that Jesus should just take what his rightfully his and establish himself as king without dying on the cross. In saying this, Peter is echoing the temptation that Jesus received from Satan in Matthew 4. Here, Satan tempts Jesus to avoid suffering and use His power for His own gain, and he says that if Jesus will only worship him, then the crown to all the kingdoms of the world will be His. In Matthew 4, Satan literally tempts Jesus with ‘the whole world in exchange for His soul’. 

Jesus is saying that it is God’s plan that He would lose His life in order that we may gain eternal life when we put our trust in him. If Jesus does not go through the cross, then He will have allowed Satan to win and we would be without hope. That’s why He is so harsh with Peter. 

But there is another point Jesus is making too. He is saying that if someone would choose to follow Jesus it must be whole-hearted, and they must be prepared for hardship and suffering - perhaps even for death! They must “deny themselves and take up their cross”. A disciple of Jesus must resist the temptation of Satan to go for the easy life. We must avoid the attitude which says: “I will follow you Jesus and do what you say, but only if life isn’t too hard”. Jesus is clear here that we must not long after material wealth, comfort or security so much that we neglect our calling to be obedient to Him. He is incredibly honest – he says the Christian life will be hard, and that we will have to endure suffering. This is important for us to know before we commit to following Him. However, he also promises that in the end there will be a great reward for those who endure all the hardship and have still have remained obedient to him.

What v26 is saying is that we have two choices: We can either choose Him now, and have a life that will entail suffering but which will gain a heavenly reward, or we can choose earthly rewards now instead of Him, and endure an eternity of suffering in Hell. When put like that, doesn’t it makes sense to choose obedience to Jesus now? 

If you want to pray this through, why don’t you pray that Jesus will help you to be obedient to Him in all things, especially when life gets hard. And pray for those people around you who have rejected Him and are in danger of Hell. Pray that you might have the courage to speak to them about the seriousness of their situation.