According to the scholars of Seerah, this miracle is referred to as the miracle of Habs-e-Shams (the stalling of the sun). Sheikh Taqiyy-ud-Deen Subki (rahimahullah) says:

وَشَمۡسُ الضُّحٰى طَاعَتۡكَ عِنۡدَ مَغِيۡبِهَا      فَمَا غَرَبَتۡ بَلۡ وَافَقَتۡكَ بِوَقۡفِهِ

“The setting sun submitted to you when it was about to set. Hence, it did not set, but it complied with you (i.e. your instruction) by stalling.”

In this manner, Allah Ta‘ala confirmed the truthfulness of Rasulullah (sallallahu ‘alaihi wasallam). The Quraish witnessed his honesty with their very own eyes and they heard the truth with their very own ears. However, they remained obstinate on their denial of the truth and were determined to continue opposing Rasulullah (sallallahu ‘alaihi wasallam) and Islam.

Some of the Quraish went to Hazrat Abu Bakr (radhiyallahu ‘anhu) and said, “Your friend (i.e. Hazrat Rasulullah [sallallahu ‘alaihi wasallam]) says that he went to Bayt-ul-Muqaddas last night and returned before dawn. Do you believe him?” Hazrat Abu Bakr (radhiyallahu ‘anhu) asked, “Did Rasulullah (sallallahu alaihi wasallam) really say that?” When they replied in the affirmative, Hazrat Abu Bakr (radhiyallahu ‘anhu) declared, “Then it has to be the truth. I wholeheartedly believe whatever he says. In fact, day and night, I believe in the heavenly news he conveys to us which is even beyond that.”

It was from that day that Hazrat Abu Bakr (radhiyallahu ‘anhu) was conferred with the title of ‘Siddeeq’.

(Extracted from Seeratul Mustafa 1/311-312)