When the foot slips, the wound can be healed; but when the tongue slips, the wound it causes in the heart of another will fester for life. The tongue is liable to four big errors; uttering falsehood, scandalizing, finding fault with others and excessive articulation. These have to be avoided. Practice moderation in speech. That will help you in many ways. The bond of brotherhood will be tightened if people speak less and speak sweet.
(From : Sai Veda, The Word of God, sayings of Bhagavan Sri Sathya Sai Baba)