Genesis 49:5
4 You are destructive like water and will not excel, for you got on your father’s bed, then you defiled it—he got on my couch! 5 Simeon and Levi are brothers, weapons of violence are their knives! 6 O my soul, do not come into their council, do not be united to their assembly, my heart, for in their anger they have killed men, and for pleasure they have hamstrung oxen.
LXX Genesis 49:5
4 You became wanton like water; do not boil over. For you went up upon your father’s bed; then you defiled the couch where you went up! 5 Symeon and Leui are brothers; they put an end to lawlessness from their midst. 6 May my soul not come into their council, and may my inward parts not press in on their company, because in their anger they killed men and in their passion they hamstrung a bull.
Notes and References
"... It is virtually impossible to determine the correct reading of the consonantal מכרתיהם, but wider context provides us firmer ground for evaluating כלו vs. כלי. Jacob’s statement is clearly meant to be negative, as he continues by saying that he will not be a part of their group because of their murderous ways, ostensibly a reference to the story in Genesis 34, in which they slaughtered the Shechemites and Jacob rebuked them. If so, we would expect this verse to be negative since it functions as a lead-up to the following two verses. Thus, it is inappropriate to say that “they put an end to lawlessness” as SP and LXX do, since this would be a positive statement, and directly contradicts what Jacob is about to say, that they are violent and lawless themselves. Thus, כלי of MT is preferable. The variant reading in SP and LXX was not created through an intentional change, but a textual mishap. The letters vav and yod look very similar, and such accidental interchanges occur hundreds of times in ancient and medieval manuscripts ..."
Tov, Emanuel The Curse of Simeon and Levi, Genesis 49:5 (pp. 1-3) Hebrew University of Jerusalem, 2018