Mark 9:1:

And he said unto them, Verily I say unto you, That there be some of them that stand here, which shall not taste of death, till they have seen the kingdom of God come with power.

See also:

Power, Then and Now
Objection: God’s Kingdom Is “Already but Not Now” – What We Will Be Has Not Appeared (1 John 3:2) and Our Lowly Bodies Have Not Been Transformed (Philippians 3:20-21)
Condition: Deafness