Sirach 13:16
Ben Sira, Ecclesiasticus12 Cruel are those who do not keep your secrets; they will not spare you harm or imprisonment. 13 Be on your guard and very careful, for you are walking about with your own downfall. 15 Every creature loves its like, and every person the neighbor. 16 All living beings associate with their own kind, and people stick close to those like themselves. 17 What does a wolf have in common with a lamb? No more has a sinner with the devout. 18 What peace is there between a hyena and a dog? And what peace between the rich and the poor? 19 Wild asses in the wilderness are the prey of lions; likewise the poor are feeding grounds for the rich. 20 Humility is an abomination to the proud; likewise the poor are an abomination to the rich.
Bava Kamma 92b
Babylonian TalmudRabba bar Mari explains each of the sources. It is written in the Torah, as it is written: “And so Esau went to Ishmael” (Genesis 28:9). It is repeated in the Prophets, as it is written: “And there were gathered vain fellows to Yiftah, and they went out with him” (Judges 11:3). And it is triplicated in the Writings, as it is written: All fowl will live with its kind, and men with those like him (Book of Ben Sira 13:17). We learned it in a mishna (Kelim 12:2): All that is attached to that which is ritually impure is ritually impure; all that is attached to that which is ritually pure is ritually pure. And we learned it in a baraita: Rabbi Eliezer says: Not for naught did the starling go to the raven but because it is its kind, as it too is a non-kosher bird.
Notes and References
"... I have given these quotations just as they are in the works from which they are taken, without putting them in verses or even providing them with stops. Such an arrangement would have implied some metrical division, which I strongly desired to avoid ... That my collection will contribute much towards solving the great Sirach difficulties, I in no way flatter myself. The quotations are too few in proportion to the bulk of the book to throw much light on the problem. I must also distinctly state that the quotations do not always exactly correspond with references given to Ecclesiasticus. Sometimes only one of many sentences of the quotation is contained in Sirach, sometimes none at all. And thus they can only be used after the closest examination. But still I venture to think that the bringing together of all the passages with their varice lectiones will be of some service to the student, as revealing the fact that the version of Ecclesiasticus known to the Rabbis was mostly written in pure Hebrew. And when the Rabbis who did not quote literally made some alteration, it was for such terms as are to be found in the Mishnah or the Barait hot, e.g., the Aboth de Rabbi Nathan ..."
Schechter, Solomon The Quotations from Ecclesiasticus in Rabbinic Literature (pp. 682-706) University of Pennsylvania Press, 1891