A.T. Robertson 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)

Doubt not (μη διακριθητε). First aorist passive subjunctive, second-class condition. To be divided in mind, to waver, to doubt, the opposite of "faith" (πιστιν), trust, confidence.

What is done to the fig tree (το της συκης). The Greek means "the matter of the fig tree," as if a slight matter in comparison with

this mountain (τω ορε τουτω). Removing a mountain is a bigger task than blighting a fig tree. "The cursing of the fig-tree has always been regarded as of symbolic import, the tree being in Christ's mind an emblem of the Jewish people, with a great show of religion and no fruit of real godliness. This hypothesis is very credible" (Bruce). Plummer follows Zahn in referring it to the Holy City. Certainly "this mountain" is a parable and one already reported in Mt 17:20 (cf. sycamine tree in Lk 17:6). Cf.Zechariah 17:4.