13. Who purified himself: Who affirmed the faith giving up disbelief and polytheism, adopted good morals giving up evil morals, and performed good deeds giving up evil deeds. Success does not imply worldly prosperity, but true and real success whether worldly prosperity accompanies it or not. (For explanation, see (E.N. 23 of Surah Younus), (E.Ns 1, 11, 50 of Surah Al-Mominoon); (E.N. 4 of Surah Luqman).
14. To remember Allah signifies His remembrance in the heart as well as with the tongue.
15. That is, he did not remain content only with remembering Allah but proved by performing the Prayer that he is also practically prepared to obey God in Whom he has affirmed the faith, and will remember His name as long as he lives. In this verse mention has been made of two things respectively: First, to remember Allah, then to perform the Prayer. Accordingly, the method enjoined is that the Prayer be begun with Allahu Akbar. This is an evidence to prove that all the elements of the procedure that the Prophet (peace be upon him) has taught of performing the Prayer, are based on the allusions in the Quran. But, no one else, apart from the Messenger (peace be upon him) of Allah, could by combining these injunctions and allusions give the Prayer the form that it has.