Matthew 18:6-7

6but 1whoever 2causes one of these little ones who believe in Me to stumble, it 3would be better for him to have a 4heavy millstone hung around his neck, and to be drowned in the depth of the sea.

7“Woe to the world because of its stumbling blocks! For 5it is inevitable that stumbling blocks come; but woe to that man through whom the stumbling block comes!