Here are some more great quotes on friendship from Hugh Black’s book, Friendship.

A faithful friend can be trusted not to speak merely soft words of flattery. It is often the spectator who sees most of the game, and, if the spectator is at the same time keenly interested in us, he can have a more unbiased opinion than we can possibly have.

There is nothing so important as the choice of friendship; for it both reflects character and affects it. A man is known by the company he keeps. This is an infallible test; for his thoughts, and desires, and ambitions, and loves are revealed here. He gravitates naturally to his congenial sphere. And it affects character; for it is the atmosphere he breathes. It enters into his blood and makes the circuit of his veins. All love assimilates to what it loves. A man is moulded into likeness of the lives that come nearest him.

If every evil man is a centre of contagion, every good man is a centre of healing. … The choice of friends is therefore one of the most serious affairs in life, just because a man becomes moulded into the likeness of what he loves in his friend.

Friends should be chosen by a higher principle of selection than any worldly one, of pleasure, or usefulness, or by weak submission to the evil influences of our lot. They should be chosen for character, for goodness, for truth and trustworthiness, because they have sympathy with us in our best thoughts and holiest aspirations, because they have community of mind in the things of the soul. All other connections are fleeting and imperfect from the nature of the case.

The only permanent severance of heart comes through lack of a common spiritual footing. If one soul goes up the mountain top, and the other stays down among the shadows, if the two have not the same high thoughts, and pure desires, and ideals of service, they cannot remain together except in form. Friends need not be identical in temperament and capacity, but they must be alike in sympathy. An unequal yoke becomes either an intolerable burden, or will drag one of the partners away from the path his soul at its best would have loved to tread.

The real source of separation is ultimately a spiritual one. We cannot walk with another unless we are agreed (Amos 3.3). The lapse of friendship is often due to this, that one has let the other travel on alone. If one has sought pleasure and the other has sought truth; if one has cumbered his life with the trivial and the petty, and the other has filled his with high thoughts and noble aspirations; if their hearts are on different levels, it is natural that they should now be apart. We cannot stay behind with the camp-followers, and at the same time fight in the van with the heroes.