In Matthew 16:20 the Lord cancelled the earlier instructions given to the disciples to announce His Messiah-ship and the nearness of that dominion on earth, centered in Jerusalem, which the prophets had predicted. From that time forth (v.21) the Lord began to lay emphasis on His impending death and resurrection, which He knew was to be the righteous basis by which both the heavenly Church and the heavenly kingdom would come into existence. Not realizing this, Peter rebuked the Lord (v.22). By revelation he knew the greatness of the Person, but he did not yet know the wonder of His work.
The Lord teaches in the following verses that the cross is the way into the heavenly things He was about to establish, not only for Himself but also for all who would follow Him. Taking of the cross entails the losing of the life of this world, but it is the door of entrance into the life that is life indeed – into that “eternal life” which is the fruit of death and resurrection. Here is found a heavenly life. Three disciples were permitted to see a sample of that life by the Transfiguration scene, which the verses that follow put on record.
Our Lord Himself introduced the heavenly things in germinal form, and His death and resurrection were shown to be the basis of their introduction. “These things,” He spoke, “being yet present.” But when the Holy Spirit was come He would teach them “all things” (Jn. 14:25-26). Thus we are brought into the full light of the heavenly things that our Lord Jesus introduced in Matthew 16.
By F. B. Hole