(21) If ye have faith, and doubt not.--The promise, in its very form, excludes a literal fulfilment. The phrase to "remove mountains" (as in 1Corinthians 13:2) was a natural hyperbole for overcoming difficulties, and our Lord in pointing to "this mountain"--as He had done before to Hermon (Matthew 17:20)--did but give greater vividness to an illustration which the disciples would readily understand. A mere physical miracle, such as the removal of the mountain, could never be in itself the object of the prayer of a faith such as our Lord described. The hyperbole is used here, as elsewhere, to impress on men's mind the truth which lies beneath it.

Verse 21. - Jesus answered. To the apostles' question the Lord makes reply, drawing a lesson, not such as we should have expected, but one of quite a different nature, yet one which was naturally deduced from the transaction which had excited such astonishment. They marvelled at this incident; let them have and exercise faith. and they should do greater things than this. Christ had already made a similar answer after the cure of the demoniac boy (Matthew 17:20, where see note). If ye have faith, and doubt not (μὴ διακριθῆτε). The whole phrase expresses the perfection of the grace. The latter verb means "to discriminate," to see a difference in things, hence to debate in one's mind. The Vulgate gives, Si habueritis fidem, et non haesitaveritis. What is here enjoined is that temper of mind which does not stop hesitatingly to consider whether a thing can be done or not, but believes that all is possible - that one can do all things through Christ who strengthens him. So the apostles are assured by Christ that they should not only be able to wither a tree with a word, but should accomplish far more difficult undertakings. This which is done to the fig tree (τὸ τῆς συκῆς); as, "what was befallen to them that were possessed with devils (τὰτῶν δαιμονιζομένων)" (Matthew 8:33). The promise may intimate that it was to be through the preaching of the apostles, and the Jews' rejection of the salvation offered by them, that the judgment should fall on the chosen people. Thus they would do what was done to the fig tree. And in the following words we may see a prophecy of the destruction of the mountain of paganism. Or it may mean that theocratic Judaism must be cast into the sea of nations before the Church of Christ should reach its full development (Lange). This mountain. As he speaks, he points to the Mount of Olivet, on which they were standing, or to Moriah crowned by the glorious temple. Be thou removed; be thou taken up; ἄρθητι, not the same word as in Matthew 17:20. The sea. The Mediterranean (see a similar promise, Luke 17:6). It shall be done. It was not likely that any such material miracle would literally be needed, and no one would ever pray for such a sign; but the expression is hyperbolically used to denote the performance of things most difficult and apparently impossible (see Zechariah 4:7; 1 Corinthians 13:2).

21:18-22 This cursing of the barren fig-tree represents the state of hypocrites in general, and so teaches us that Christ looks for the power of religion in those who profess it, and the savour of it from those that have the show of it. His just expectations from flourishing professors are often disappointed; he comes to many, seeking fruit, and finds leaves only. A false profession commonly withers in this world, and it is the effect of Christ's curse. The fig-tree that had no fruit, soon lost its leaves. This represents the state of the nation and people of the Jews in particular. Our Lord Jesus found among them nothing but leaves. And after they rejected Christ, blindness and hardness grew upon them, till they were undone, and their place and nation rooted up. The Lord was righteous in it. Let us greatly fear the doom denounced on the barren fig-tree.Jesus answered and said unto them,.... His disciples wondering at his power, in causing the fig tree to wither so suddenly:

verily I say unto you, if ye have faith; that is, in God, in his power, which reaches to all things: the object of faith is expressed in Mark, and by way of exhortation, "have faith in God", that he will enable you to perform whatsoever ye shall desire; which must be understood, not of spiritual faith in the promises of God, and person of Christ, but of, the faith of miracles, or faith in the power of God to perform things that are above the strength of nature:

and doubt not; either of the power, or will of God to do for you, and by you, the thing desired; for this kind of faith would not admit of the least degree of doubting: there must be no hesitation in the mind, no reasoning upon the thing, how it can be performed; the mind must not be divided between the power and will of God, and the difficulties and discouragements which attend the case, but must believe in hope against hope, with a full persuasion of accomplishment: for want of this faith, without doubting, the disciples could not cure the child that was lunatic.

Ye shall not only do this which is done to the fig tree; cause one to be dried up, and wither away by a word, as Christ had done to this, which, comparatively speaking, was but a lesser sort of miracle;

but also, if ye shall say to this mountain; the Mount of Olives, where Christ and his disciples now were, and were passing over, or, at least, were very near it; or any other mountain wherever they might be, to which they should, upon any occasion, think fit to say,

be thou removed, and cast into the sea; which was many miles off from Mount Olivet, and must he a very surprising performance for a mountain to be rooted up, so large as that was, and be carried several miles from its former situation, and be thrown into the sea; and yet, as difficult and amazing as this may seem,

it shall be done: that is, provided the person doubts not; or, as it is said in Mark, "shall not doubt in his heart, but shall believe that those things, which he saith, shall come to pass, he shall have whatsoever he saith": for this must not be confined to the particular instances of drying up a fig tree, or removing a mountain, but the doing of any sort of miracle, how great soever. Nor is it our Lord's meaning that they should do these particular things; nor is it certain that they ever did: but his sense is, that, had they faith, they should be able not only to do such lesser miracles, as, comparatively speaking, the withering of the fig tree was, but they should be able to perform things much more difficult and surprising, whenever the good of the souls of men, the propagation of the Gospel, and the glory of God required them.