Jesus had just finished asking the disciples whom people thought He was. Now, He wants to know whom they say He is. Jesus knows their thoughts, but He wanted them to know their thoughts. Jesus is the perfect teacher to bring out of our soul the knowledge of what we really believe. Here is my translation and notes.
20 He said to them, “But whom do youp say that I am?” Peter answering said, “The Christ of God.”
21 He strictly ordered and commanded them to tell no one.
[The reason Jesus commanded them to not tell anyone is because, according to Dr Arnold Fruchtenbaum, the people have rejected the public ministry of Jesus and so Jesus now restricts His teaching mainly to only His disciples. Individuals can still seek truth from Jesus].
22 He said, “The Son of Man must suffer many things, be rejected by the elders, chief priest, and scribes, be killed, and be raised the third day.”
[Jesus speaks of the future, for He is a prophet and omniscient, for He is God].
23 He said to all, “If any wants to follow me, let him deny himself, take up his cross daily, and follow me,
24 “For whoever wants to save his life will lose it, but whosoever will lose his life for my sake, this one will save it.
[Doing and living God’s will is more important than our will. Some sell their soul to the devil to receive what they lust for, but Christians surrender our lives to do God’s will. Doing God will is preparing us for the Kingdom of God, its rules, and Jesus’s reign].
25 “For what does a man profit if in gaining the whole world is himself destroyed or [suffers] spiritual loss?
[The Greek word for destroyed is ἀπόλλυμι apóllymi (G622). It means rendered useless and ruined. The Lord is comparing business profit and loss to illustrate spiritual profit and loss. Loss doesn’t necessarily refer to loss of salvation but to rewards (1 Corinthian 3:11-15). The Greek word for [suffers] spiritual loss is ζημιόω zēmióō (G2210). It means giving up something. TDNTa adds: In the one instance in the Synoptics (Matthew 16:26; parallel passages in Mark 8:36, and Luke 9:25), the antithesis “gain” suggests the commercial figure of profit and loss. To gain the whole world one must lose (i.e., pay the price of) the self—a poor exchange. If a person sets their heart on money (1 Timothy 6:10), instead of spiritual treasure, they gain physical treasure but suffering spiritual loss. Again, this doesn’t necessarily refer to loss of salvation. The person who does set their heart on physical treasure is making a god/idol, which is breaking the first commandment (Exodus 20:3). See 1 Timothy 6:17, Philippians 3:18-19, and Hebrews 13:5].
26 “For whosoever is ashamed of me and my words, the Son of God will be ashamed of him when he comes in his own glory, [his] Father’s [glory], and of the holy angels.
27 “But I tell youp the truth, there are some standing here who will not experience death until they see the Kingdom of God.”
[Most refer this to the Transfiguration of Jesus in the next verse. Compare 2 Peter 1:16-18. The Transfiguration is a foretaste of the Kingdom of God, especially occurring in the Millennium].