Be courteous to all, but ...

Be courteous to all, but intimate with few, and let those few be well tried before you give them your confidence.
Be courteous to all, but intimate with few, and let those few be well tried before you give them your confidence.

More phrases

It really is all about believing in yourself: 80 per cent mental, 20 per cent physical.
 Victoria Pendleton
Courage - a perfect sensibility of the measure of danger, and a mental willingness to endure it.
 William Tecumseh Sherman
Regardless of how you feel inside, always try to look like a winner. Even if you are behind, a sustained look of control and confidence can give you a mental edge that results in victory.
 Diane Arbus
Courage is rightly esteemed the first of human qualities... because it is the quality which guarantees all others.
Optimism is the faith that leads to achievement. Nothing can be done without hope and confidence.

Quotes from the same author

True friendship is a plant of slow growth, and must undergo and withstand the shocks of adversity, before it is entitled to the appellation.
It is far better to be alone, than to be in bad company.
To be prepared for war is one of the most effective means of preserving peace.
Among many other weighty objections to the Measure, it has been suggested, that it has a tendency to introduce religious disputes into the Army, which above all things should be avoided, and in many instances would compel men to a mode of Worship which they do not profess.
My mother was the most beautiful woman I ever saw. All I am I owe to my mother. I attribute all my success in life to the moral, intellectual and physical education I received from her.