Da'wah - inviting people towards Islam - is one of the obligations a Muslim must perform. Dawah includes clarifying the misconceptions, presenting the true picture of Islam, inviting to righteousness, forbidding evil, and help the society maintain peace and harmony. It never involves coercion, undue influence, fraud, or disrespect.
As a Muslim one must perform this duty of clarifying and presenting the message of Islam to those who are misinformed, dis-informed, or uninformed. The Quran says, "Invite (all) to the way of your Lord with wisdom and fair preaching and argue with them in ways that are best and most gracious." (16:125).
The 14 principles of Dawah: Shaykh Muhammad bin Saleh Al-Uthaymin
- Adhering to the Quran and Sunnah.
- Knowledge and Insight (Basirah).
- Mutual Love and Good Relations.
- Patience and Bearing Hardship, keeping in mind Allah’s reward for doing so.
- Adorning Oneself with Excellent Manners.
- Breaking the Barriers between Caller and the People.
- The use of Kindness and Gentleness.
- The youths should be open minds and hearts regarding differences among scholars.
- Controlling one’s emotions according to the dictates of the Shariah and of the sound mind.
- Scheduling of reciprocal visits and trips among the youths.
- One should not lose hope upon witnessing mush falsehood and evil.
- Communicate with those who are in Authority.
Source: The Islamic Awakening (download the whole book (pdf))