Matthew 16:27-28 For the Son of Man will come in the glory of His Father with His angels, and then He will reward each according to his works. 28 Assuredly, I say to you, there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom."

How could this be more clear? Jesus is is speaking to His disciples. He does not mislead them or lie to them. He makes the fact known that there were some of His disciples who would be alive when He returned.

Another interesting point is that Jesus told Peter "What is it to you if I keep John alive until my second coming? John 21:22.

Another thing I want to point out is many Christians were taught that Matthew 16 is referring to the transfiguration. This cannot be true because then it would not make any sense for Jesus to say "six days from now some of you will not taste death until you see Me come in My kingdom"? That would not be so amazing. Were there rewards for every man according to their works after the six days? No! and this proves it is not referring to the transfiguration. It does make sense that some of His disciples would be alive when He would reward every man according to his works in Revelation 22:12 "And behold, I am coming quickly, and My reward is with Me, to give to every one according to his work.

Most Christians know that when Jesus uses the phrase, verily, verily it never introduces a new subject or idea. Therefore, Matthew 16:27-28 could not be referring to the transfiguration. 2 Peter 1:16-19 explains that the transfiguration was a proof that what Jesus said in Matthew 16:27,28 was going to take place. The whole purpose of the transfiguration of Jesus was to prove to the disciples that He was not lying. He would come back before some of them would taste death.

In Matthew 21:33-45 Jesus makes sure His audience knows He is referring to them! not to someone else 2,000 years later.