If I mayn't tell you what I feel, what is the use of a friend?

Thackeray

I take of worthy men whate'er they give:
Their heart I gladly take, if not, their hand;
If that, too, is withheld, a courteous word,
Or the civility of placid looks.

Joanna Baillie

Friendship maketh a fair day in the affections, from storm and tempest; but it maketh daylight in the understanding, out of darkness and confusion of thoughts.

Bacon

He who will not to friends' advice attend;
Must not complain when they him reprehend.

Saadi

There is no such flatterer as is a man's self, and there is no such remedy against flattery of a man's self as the liberty of a friend.