How do we invite people to Islam when addressing matters of ijtihad; do we favor what we have concluded, or do we present the different schools of thought with their contradictory opinions, such as the issue of a Muslim being killed for (killing) a non-Muslim?

Whoever invites non-Muslims to Islam should begin with Tawhid (monotheism) and faith, then the pillars of Islam, then matters of religious practice, progressing from the most important to the important, and from minor knowledge to major knowledge. In doing so, they should observe the principle of "Rabbaniyyah (divine-oriented teaching) in education." Ibn Abbas said, "Be Rabbaniyyin": forbearing and فقهاء (jurists). It is said: The Rabbani is one who educates people with minor knowledge before major knowledge.

This is based on the saying of the Prophet, peace be upon him, to Mu'adh ibn Jabal when he sent him to the people of Yemen: «Indeed, you are going to a people from the People of the Book. So let the first thing you invite them to be to وحده (affirm the Oneness of) Allah the Almighty. If they come to know that, then inform them that Allah has enjoined upon them five prayers in their day and night. If they pray, then inform them that Allah has enjoined upon them zakat (charity) upon their wealth, to be taken from their rich and given to their poor.» [Al-Bukhari and Muslim].

As for interpretive (ijtihadi) issues, Muslims in general should differentiate between religion as an infallible revelation and our understanding of the branches of religion, its details, and the application of its rulings to reality. In the latter, there is disagreement and variation.

As for the issue of restricting oneself to what the caller considers preponderant, or mentioning differing opinions and schools of thought, it varies according to the situation and the needs of the one being invited.