Sayyiduna Ibn Umar (may Allah be pleased with them both) reports that the Messenger of Allah (peace and blessings be upon him) said: "Religion is sincerity (well-wishing)." It was asked: "O Messenger of Allah! For whom?" He (peace be upon him) replied: "For Allah, for His Messenger, for His Book, for the leaders and rulers of the Muslims, and for the common Muslims."
Explanation – In this hadith, Islam has been described as goodwill (naseehah), meaning to have goodwill towards everyone and to safeguard the rights of every rightful person. Thus, goodwill towards Allah Ta’ala is to have faith in Him, to affirm His oneness (tawheed), and not to associate anyone with Him. Goodwill towards the Book of Allah is to have faith in it and to act upon it. Goodwill towards the Prophet and Messengers means to have faith in them, to honor and respect them, and to follow them. Goodwill towards the leaders (a’immah) of the Muslims is to always guide them, to give them good advice, and to obey them in lawful matters. As for goodwill towards the common Muslims, it is to be mindful of their religious and worldly benefit and harm, and to fulfill the rights that have been prescribed for them.