From Thomas à Kempis

Do not care much who is with you and who is against you; but make it your greatest care that God is with you in everything you do.

That is, seek to please only Him. We are often too concerned with what others think of us.

Do not think that you have made any progress unless you feel that you are the lowest of men.

Perhaps there is hope for me yet.

You are good at excusing and justifying your own deeds, and yet you will not listen to the excuses of others. It would be more just to accuse yourself  and to excuse your brother.

I have long observed this tendency of ours. This is most excellent advice for marriage, too.