1. A sign of a lover of wisdom is his delight in not running his mouth about things he doesn't know.
2. Who cares for your beauty if your tongue is ugly.
3. I was sitting with the Prophet (pbuh) when two men began to quarrel and curse each other and the face of one of them turned red and the veins of his neck were swollen (from rage). Messenger of Allah (pbuh) said,
"I know of a word, if he were to utter that, his rage would vanish and that is:
A'udhu billahi minash-Shaitan nir-rajim
(I seek refuge with Allah from Satan, the accursed)."
So they (Companions) said to him: "The Prophet (pbuh) tells you to utter: 'I seek refuge with Allah from Satan, the accursed".
4. The tongue is but a small soft flesh. yet it is capable of breaking the strongest bonds and destroying the most powerful of relationships.
5. Patience (Sabar) is that the heart does not feel anger towards that which is destined, and the mouth does not complain.
6. The tongue is only a messenger of the heart.
7. Conceal your heart, control your mouth. Beware of releasing the restraints in you; Listen if you want to endure in the mouth of the hearers. Speak after you have mastered the craft.
8. The tongue has no bones but is strong enough to break a heart. So be careful with your words.
9. He who is two-faced in this world will have two tongues of fire on the Day of Resurrection.
Sunan Abi Dawud 4873
10. Sometimes you have to decide which will hurt more: biting your tongue or having your say.
11. "Whoever believes in Allah and the Last Day, should not hurt his neighbor and whoever believes in Allah and the Last Day, should serve his guest generously and whoever believes in Allah and the Last Day, should speak what is good or keep silent."
[Sahih al-Bukhari 6136]
12. Fill your mind before you empty your mouth.
13. The tongue like a sharp knife. Kills without drawing blood.
14. A person’s tongue can give you a taste of his heart.
15. Never trust your tongue when your heart is bitter.
16. Talk with your mind before you talk with your tongue.
17. The words of the tongue should have three gatekeepers:
Is it true?
Is it kind?
Is it necessary?