'Stumbling block' in the Bible

and he having turned, said to Peter, 'Get thee behind me, adversary! thou art a stumbling-block to me, for thou dost not mind the things of God, but the things of men.'

'Woe to the world from the stumbling-blocks! for there is a necessity for the stumbling-blocks to come, but woe to that man through whom the stumbling-block doth come!