اللَّهُمَّ أَعِنِّي عَلَى ذِكْرِكَ وَشُكْرِكَ وَحُسْنِ عِبَادَتِكَ
Allahumma a'inni 'ala dhikrika wa shukrika wa husni 'ibadatik
Ee Allah, nisaidie kukukumbuka, kukushukuru, na kukuabudu vizuri.
Recite after every obligatory prayer
The Prophet (PBUH) took Muadh ibn Jabal's hand and said: 'O Muadh, I love you. Do not forget to say this after every prayer.'