IN ISLAM:
Actions Manifest the Belief
The Hadith starts off by the Prophet’s statement “Whoever believes in Allah and the Day of Judgment,” then He (sas) resumes his Hadith talking about the Muslims’ action, which indicates that actions are part of our belief. It is not enough that we are Muslims or it is not enough that we say that we believe in Allah (swt) and in the Prophet (peace be upon him) but also this belief should manifest one’s actions. That is why the scholars said, “Belief is what settles in the heart and manifest itself on one’s limbs.” It is part of Islam to act on what you believe in and act upon the teachings of the prophet (peace be upon him) and the teachings of the Quran.

The Prophet (sas) put emphases on the importance of each action by repeating the statement “Whoever believes in Allah and the Day of Judgment,” with every single action. It is a constant repetition and reminder that these actions should come out of one's belief.