'Stumbling blocks' in the Bible

The Son of man will send forth his angels, and they will gather out of his kingdom all the stumblingblocks, and those who do iniquity,

Woe to the world because of stumblingblocks! For it must needs be that stumblingblocks come; but woe to the man through whom the stumblingblock cometh!

And he said to his disciples, It is impossible but that stumblingblocks will come; but woe to him through whom they come!