To tell tales out of school.

Two heads are better than one.

To hold with the hare and run with the hound.

It hurteth not the tongue to give fair words.

To whom thy secret thou dost tell, to him thy freedom thou dost sell.

Trust not him with your secrets, who, when left alone in your room, turns over your papers.

If you reveal your secrets to the wind, you should not blame the wind for revealing them to the trees.