Hadithcore
Hadith #2104020

Narrated Mu'adh bin Jabal (RA) Allah's Messenger (ﷺ) told me, "O Mu'adh, I will give you some advice - Never leave the recitation of this supplication after every prayer:

'O Allah, help me to remember You, thank You, and worship You perfectly.'" [Ahmad, Abu Dawud and an-Nasa'i reported it through a strong chain of narrators].

وَعَنْ مُعَاذِ بْنِ جَبَلٍ ‏- رضى الله عنه ‏- { أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-قَالَ لَهُ : " أُوصِيكَ يَا مُعَاذُ : لَا تَدَعَنَّ دُبُرَ كُلِّ صَلَاةٍ أَنْ تَقُولُ : اَللَّهُمَّ أَعِنِّي عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ } رَوَاهُ أَحْمَدُ , وَأَبُو دَاوُدَ , وَالنَّسَائِيُّ بِسَنَدٍ قَوِيٍّ .‏ [1]‏

References2 variants
Sunnah.com reference
Book 2, Hadith 219
Arabic/English book reference
Book 2, Hadith 323