اللهم أعني على ذكرك, وشكرك, وحسن عبادت
Allahumma a’inee ‘ala dhikrika, wa shukrika, wa husni ibadatik.
Mu`adh ibn Jabal (May Allah be pleased with him) reported: Messenger of Allah (PBUH) held my hand and said, “O Mu`adh, By Allah, I love you and advise you not to miss supplicating after every Salat (prayer) saying: `Allahumma a`inni `ala dhikrika wa shukrika, wa husni `ibadatika,’ (O Allah, help me remember You, expressing gratitude to You and worship You in the best manner)”.
[Abu Dawud and An-Nasa'i].