Deuterocanon

Sirach 6:16

Ben Sira, Ecclesiasticus

14 Faithful friends are a sturdy shelter: whoever finds one has found a treasure. 15 Faithful friends are beyond price; no amount can balance their worth. 16 Faithful friends are life-saving medicine; and those who fear the Lord will find them. 17 Those who fear the Lord direct their friendship aright, for as they are, so are their neighbors also. 18 My child, from your youth choose discipline, and when you have gray hair you will still find wisdom.

Date: 195-175 B.C.E.
* Dates are based on scholarly estimates

Ambrose On the Duty of the Clergy 2.7

37 It gives a very great impetus to mutual love if one shows love in return to those who love us and proves that one does not love them less than oneself is loved, especially if one shows it by the proofs that a faithful friendship gives. What is so likely to win favour as gratitude? What more natural than to love one who loves us? What so implanted and so impressed on men's feelings as the wish to let another, by whom we want to be loved, know that we love him? Well does the wise man say: Lose your money for your brother and your friend. And again: I will not be ashamed to defend a friend, neither will I hide myself from him. If, indeed, the words in Ecclesiasticus testify that the medicine of life and immortality is in a friend; yet none has ever doubted that it is in love that our best defense lies. As the Apostle says: It bears all things, believes all things, hopes all things, endures all things; love never fails.

Date: 390-395 C.E.
* Dates are based on scholarly estimates