And he said, If ye had faith as a grain of mustard seed — If ye had the least measure of true faith, no instance of duty would be too hard for you. Ye would say to this sycamine tree — This seems to have been a kind of proverbial expression.
Related Commentaries of Luke 17:6
Luke 17:6
6 And the Lord said,If ye had faith as a grain of mustard seed, ye might say unto this sycamine tree, Be thou plucked up by the root, and be thou planted in the sea; and it should obey you.