As for those who strive in Us,
We surely guide them to Our paths (Quran)
A description of the following related video clip, is given bellow:
A Sunni scholar: Umar Bin AL-Khattab changed the Adhan!!!
The Scholar, and based on the Sunni soundest of all chains of transmission, which is "Malik, from Nafi`, from Ibn `Umar", explained how Umar changed the Adhan, where Imam Malik ibn Anas has narrated in his al-Muwatta' that during the caliphate of 'Umar the Mu'azzin came to call him for the dawn prayer and found him asleep.
He said: As-salatu Khayrum minan nawm (Prayer is better than sleep);
'Umar woke up and ordered the Mu'azzin to include it in the Adhan of Fajr."
Also, based on the same source (which is supported by many other sources), the scholar has showed that the original contains the phrase “hayya ‘ala khayril ‘amal” (come to the best of deeds); however, at the time the Islamic state was expanding, the second caliph, ‘Umar ibn al-Khattab thought that this phrase would discourage people from performing jihad (defense fighting) and thus ordered it to be removed from the adhan!!!