Allah describes the successful believers in surah al-Nur by saying:
وَمَن يُطِعِ اللَّـهَ وَرَسُولَهُ وَيَخْشَ اللَّـهَ وَيَتَّقْهِ فَأُولَـٰئِكَ هُمُ الْفَائِزُونَ
And whoever obeys Allah and His Messenger, fears Allah, and exercises taqwa of him – these ones are the successful ones. [24:52]
In part of his commentary on this ayah, sheikh ‘Abd al-Rahman ibn Naasir al-Sa’di wrote:
فقال: ومن يطع الله ورسوله فيصدق خبرهما ويمتثل أمرهما، ويخش الله أي: يخافه خوفا مقرونا بمعرفة، فيترك ما نهى عنه، ويكف نفسه عما تهوى، ولهذا قال: ويتقه بترك المحظور؛ لأن التقوى -عند الإطلاق- يدخل فيها فعل المأمور، وترك المنهي عنه، وعند اقترانها بالبر أو الطاعة – كما في هذا الموضع – تفسر بتوقي عذاب الله، بترك معاصيه، ـ
وَمَن يُطِعِ اللَّـهَ وَرَسُولَهُ
and whoever obeys Allah and His messenger
so he affirms what they have informed him of and complies with their commands
meaning, he holds a fear of Allah that is coupled with knowledge, so he therefore abandons what Allah has prohibited for him and restrains himself from what he unlawfully desires. And because of this Allah said,
and exercises taqwa of him
by leaving off the forbidden actions.
For when the term “al-taqwa” is used on its own, then it includes both the performance of the commands and the abandonment of the prohibitions. However, when it is paired with the terms “al-birr” (righteousness) or “al-taa’ah” (obedience) – as it is in this instance – then it is explained as warding off Allah’s punishment by not disobeying Him.
فأولئك الذين جمعوا بين طاعة الله وطاعة رسوله وخشية الله وتقواه هم الفائزون بنجاتهم من العذاب؛ لتركهم أسبابه، ووصولهم إلى الثواب؛ لفعلهم أسبابه
these ones …
those who have combined obedience to Allah, obedience to His messenger, fear of Allah and taqwa of Him
… are the successful ones
due to their being saved from His punishment, which is a result of their abandoning the means which lead to that, and due to their attaining Allah’s reward, which is a result of their taking the means which lead to that.
[Taysir al-Kareem al-Rahman pg. 669]
See also: Qualities of the Successful Believers Series from sheikh Muhammad al-Ameen al-Shinqitee’s explanation of the first part of surah al-Mu’minoon