What distinguishes Islam from other religions, and what is the meaning of "Lā ʾilāāh ʾillā-llāh"?

The meaning of "Lā ilāha illā Allāh" (There is no god but Allah) is that none truly deserves worship except Allah alone. Islam is the only acceptable religion to Allah, and all prophets and messengers were sent with it. Islam is characterized by its congruence with sound human nature (fitra) and its harmony with human needs, whereas other religions contradict the fitra and are filled with contradictions. It is recommended to care for new Muslims and teach them the fundamentals of the religion.