With the declaration of Prophethood, just and honest people started gathering around Him and started attaining the honor of being His companions (Sahabah). Even those who did not embrace Islam acknowledged His honesty, upright character, excellence, superiority and all other distinguishing attributes of His. As Almighty Allah SWT created Him free of all shortcomings and defects, He SWT named Him as “Muhammad” (Sallallahu alaihi wa sallam) and included this name in His Kalima. Every aspect of His life and character testifies to the truth of Tauheed (Oneness of Allah SWT) and is the proof of Islam. For this reason, in the Holy Quran, Allah SWT swears by life of the Holy Prophet (Sallallahu alaihi wa sallam).
By thy life (O Muhammad) they moved blindly in the frenzy of approaching death. Surah Hajr (15:72).
By the command of Allah SWT, the Holy Prophet (Sallallahu alaihi wa sallam) presented His blessed life as the proof of Islam. He (Sallallahu alaihi wa sallam) said
Say: If Allah had so willed I should not have recited it to you nor would He have made it known to you. I dwelt among you a whole lifetime before it (came to me). Have ye then no sense? Surah Younus (10:16)