1 Enoch 48:9
9 And I will give them over into the hands of Mine elect: As straw in the fire so shall they burn before the face of the holy: As lead in the water shall they sink before the face of the righteous, And no trace of them shall any more be found. 10 And on the day of their affliction there shall be rest on the earth, And before them they shall fall and not rise again: And there shall be no one to take them with his hands and raise them: For they have denied the Lord of Spirits and His Anointed. The name of the Lord of Spirits be blessed.
Matthew 18:6
4 Whoever then humbles himself like this little child is the greatest in the kingdom of heaven. 5 And whoever welcomes a child like this in my name welcomes me. 6 “But if anyone causes one of these little ones who believe in me to sin, it would be better for him to have a huge millstone hung around his neck and to be drowned in the open sea. 7 Woe to the world because of stumbling blocks! It is necessary that stumbling blocks come, but woe to the person through whom they come.
Notes and References
"... Both Greeks and Jews used “stumble” figuratively; for Jews, it often meant “sin” or “fall away from the faith.” Millstones were used to grind meal. They were extremely heavy, and the term here refers to the heavier kind of millstone turned by a donkey, rather than the lighter kind a woman would use. One of the most horrible punishments executed by Romans (abhorred by Jews) was to tie a person in a sack and throw them into a large body of water. Death at sea was considered terrible; some pagans believed that the ghost of the unburied would hover forever over the spot where the person had drowned. Others could apply this image to judgment (compare 1 Enoch 48:9). Jewish teachers sometimes warned of judgments with, “Better for a person who . . . than if ... ” (compare also Matthew 26:24) ..."
Keener, Craig S. The IVP Bible Background Commentary: New Testament (p. 90) InterVarsity Press, 2014