"Verily, I say to you, there are some standing here who will not taste of death till they see the Son of Man coming in his Kingdom."
…Now after six days Jesus took Peter, James, and John his brother, led them up on a high mountain by themselves. (Matthew 16:28, and 17:1-9)
And He said to them, "Assuredly, I say to you that there are some standing here who will not taste of death till they see the Kingdom of God present with power."
…Now after six days Jesus took Peter, James, and John, and led them up on a high mountain apart by themselves; and He was transfigured before them. (Mark 9:1-10)
"But I tell you truly, there are some standing here who shall not taste death till they see the Kingdom of God."
…Now it came to pass, about eight days after these sayings, that He took Peter, John, and James and went up on the mountain to pray. (Luke 9:27-37)
Why the two accounts (Matthew and Mark) saying six days, but Luke says about eight days.
Is it because Jesus often spoke of things, more than once, that were significant of things present (physical) and those things which are to come (spiritual)?
Did Peter, John and James see His Glory, only temporarily (in a vision), as a preview of that which is to come, when He (Jesus) was transfigured before them?
John surely must have had this in mind, when he said, "…And, we beheld His Glory…" (John 1:14). After all, he was an eye witness to the life of Christ.
Peter also said, "For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty." (2 Peter 1:16-18)
Could it be that there were those, then, who had not presently tasted of the physical death, as well as that of the second death, perhaps, those who will not see until - "they see"…in the presence of the Lamb (Revelation 14:10)?
I believe that Marks words are closer to the meaning of His Words – "present with power," than that given by Luke or even Matthew, and represents the second coming of Christ in His (Fathers) Glory, not merely as a preview (vision) of things to come.
Regardless of the type of Death; Physical or Spiritual - Jesus spoke the truth, as there were those who had not yet tasted the first death (although they are long dead by now), and there are those who will/shall not taste of the second death, until they are in His Presence!
When the Lord comes EVERYONE will be resurrected; the righteous to the resurrection of life and the unrighteous to the resurrection of judgment. Those who do not go through judgment in this present life will be "Judged" at the Great White Throne Judgment.
God defines the "Judgment" as returning back to righteousness, or setting things right (Psalm 94:15)
JER
The Second Death is the dying to, or death of sin – for the fleshly mind is enmity against God.