Teach ye the Cause of God, O people of Bahá,..

Say: Teach ye the Cause of God, O people of Bahá, for God hath prescribed unto every one the duty of proclaiming His Message, and regardeth it as the most meritorious of all deeds. Such a deed is acceptable only when he that teacheth the Cause is already a firm believer in God, the Supreme Protector, the Gracious, the Almighty. He hath, moreover, ordained that His Cause be taught through the power of men’s utterance, and not through resort to violence. Thus hath His ordinance been sent down from the Kingdom of Him Who is the Most Exalted, the All-Wise.  Beware lest ye contend with any one, nay, strive to make him aware of the truth with kindly manner and most convincing exhortation. If your hearer respond, he will have responded to his own behoof, and if not, turn ye away from him, and set your faces towards God’s sacred Court, the seat of resplendent holiness.
Dispute not with any one concerning the things of this world and its affairs, for God hath abandoned them to such as have set their affection upon them. Out of the whole world He hath chosen for Himself the hearts of men—hearts which the hosts of revelation and of utterance can subdue. Thus hath it been ordained by the Fingers of Bahá, upon the Tablet of God’s irrevocable decree, by the behest of Him Who is the Supreme Ordainer, the All-Knowing.

Gleanings From the Writings of Bahá’u’lláh