I am not of that feather to shake off
My friend when he must need me.

Shakespeare

The faults of our friends ought never to anger us so far as to give an advantage to our enemies.

Lord Chesterfield

Love is and was my Lord and King,
And in his presence I attend
To hear the tidings of my friend,
Which every hour his couriers bring.

Tennyson

So Life's year begins and closes;
Days, though short'ning, still can shine;
What though youth gave love and roses,
Age still leaves us friends and wine.

Thomas Moore