Expositor's Bible Commentary Commentary Matthew 21:21

"And Jesus answered and said unto them, Verily I say unto you, If ye have faith, and doubt not, ye shall not only do what is done to the fig tree, but even if ye shall say unto this mountain, Be thou taken up and cast into the sea, it shall be done." — Matthew 21:21 (ASV)

Verse 20 may be read as either a question or an exclamation. The substance of Jesus’ response has already been given in 17:20 (see comment). Here, however, attention shifts from concern about the amount of faith to the opposition of faith to doubt. The miracle Jesus selects to teach the power of faith —throwing a mountain into the sea (v.21)—is no more than a hyperbolic example of a miracle.

Jesus used the fig tree to teach the power of believing prayer. But belief in the NT is never reduced to forcing oneself to “believe” what one does not really believe. Instead, it is related to genuine trust in God and obedience to and discernment of his will. Such faith reposes on the will of God who acts.