Luke 17:1-6

And he said unto his disciples, It is impossible but that occasions of stumbling should come; but woe unto him, through whom they come! It were well for him if a millstone were hanged about his neck, and he were thrown into the sea, rather than that he should cause one of these little ones to stumble. Take heed to yourselves: if thy brother sin, rebuke him; and if he repent, forgive him. And if he sin against thee seven times in the day, and seven times turn again to thee, saying, I repent; thou shalt forgive him. And the apostles said unto the Lord, Increase our faith. And the Lord said, If ye had faith as a grain of mustard seed, ye would say unto this sycamine tree, Be thou rooted up, and be thou planted in the sea; and it would obey you.