The Mu’azzin being from among the best servants of Allah Ta’ala

عن ابن أبي أوفى قال : قال رسول الله صلى الله عليه و سلم : إن خيار عباد الله الذين يراعون الشمس والقمر والنجوم والأظلة لذكر الله (الترغيب والترهيب 1/246)

Hazrat ibn Abi Aufah (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “Certainly the best servants of Allah Ta’ala are those who observe the rising and setting of the sun, the moon, the stars and the (length of the) shadows for the remembrance of Allah Ta’ala (i.e. they fulfil their ibaadaat in its proper time according to the command of Allah Ta’ala while keeping track of time through observing the sun, moon, stars and the length of the shadows as explained in the Ahaadith. The mu’azzin is included in this glad tiding on account of him keeping track of time so that he can call out the azaan of each salaah at its proper time).”