One more interesting insight from Islamic perspective:
When it seems you might slip and fall, they are there with ropes of faith that tie around you and pull you up and onward. The Prophet gave a beautiful analogy of this sort of friendship saying, “The good companion and the bad companion are like the bearer of musk and the one who pumps from the bellows. With the bearer of musk, he will give you a share, or you will buy from him, or you will smell a pleasant scent from him; but the one who pumps the bellows, either he will burn your clothes or you will smell a foul stench from him.” [Imam Al-Bukhari and Imam Muslim]