Matthew 21:22 - Ellicott's Commentary On The Whole Bible

All things, whatsoever ye shall ask in prayer. — Here again there is the implied condition (as in Matthew 7:7) that what is asked is in harmony with the laws and will of God. If it were not so it would not be asked in faith, and every true prayer involves the submission of what it asks to the divine judgment. The words suggest the thought, of which we have the full expression in John 11:42, that our Lord’s miracles were less frequently wrought by an inherent supernatural “virtue” — though this, also, distinctly appears, e.g., in the history of the woman with the issue of blood (Luke 8:46) — than by power received from the Father, and in answer to His own prayers.