The wonder of the disciples was the consequence of imperfect faith, for this was no great thing for God to do; since then they did not clearly know His power, their ignorance made them break out into wonder.
And therefore it is added, “And Jesus answering saith unto them, Have faith in God. For verily I say unto you, That whosoever shall say unto this mountain,” &c. That is; Thou shalt not only be able to dry up a tree, but also to change a mountain by they command and order.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).