Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: “The Prophet (peace and blessings be upon him) taught us, “No one can be a believer until he/she loves for his/her brother/sister that which he/she loves for his/her own self.” Since there is nothing for us dearer than Islam, we must certainly love to share it with others. The Prophet (peace and blessings be upon him) said, “If a single person were to be guided aright through you that is better for you than having the whole world as a treasure!”
So one should never hesitate in sharing the message of mercy with their Christian friends. we should continue to deal with them most compassionately, in spite of their religious affiliations.
Islam is a continuation and confirmation of the message delivered by all prophets before Muhammad, the last of them was Jesus (peace be upon him). In fact, countless Christians in every generation entered Islam simply because of their deep conviction that the message brought by Prophet Muhammad SAW is a fulfilment of the mission of Jesus. So never present Islam as something altogether new, but as affirming the pristine truths brought by all prophets. On deeper reflection and inquiry, we also find that this is now being corroborated by statements and observations of some of the Christian theologians themselves. A general awareness is slowly emerging among them that the pristine teachings of Jesus are to be found in the Qur’an and no where else.
So by following Islam, one is seeking to be more Jesus-like; he is in fact being true to the pristine teachings of Jesus.