Three types:
| Friendship of utility | mutual usefulness | temporary |
| Friendship of pleasure | mutual enjoyment | temporary |
| Friendship of virtue | mutual respect & admire | long lasting |
Proverbs 18:24 A man of many companions may come to ruin,
but there is a friend who sticks closer than a brother. 濫交朋友，自取敗亡；但有一友，卻比弟兄更親密
Proverbs 13:20 Whoever walks with the wise becomes wise,
but the companion of fools will suffer harm. 與智慧人同行的，必得智慧；和愚昧人作伴的，必受虧損。
“Show me your friends, and I will show you your future.”; “You are the average of your five closest friends.”
Proverbs 17:17 A friend loves at all times,
and a brother is born for adversity. 朋友乃時常親愛，弟兄為患難而生。
Friendship of Jonathan and David: 1 Samuel 18: 1b 3-4; Philippians 2:3–4; Romans 12:10; 1 Samuel 20:3-4 4 Jonathan said to David, “Whatever you want me to do, I’ll do for you.”