Luke 17:3

Then said he unto the disciples, It is impossible but that offences will come: but woe unto him, through whom they come!

It were better for him that a millstone were hanged about his neck, and he cast into the sea, than that he should offend one of these little ones.

And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.

And the apostles said unto the Lord, Increase our faith.