Abdullah ibn Busr reported: A man said, “O Messenger of Allah, the laws of Islam are too many for me, so tell me something I can hold onto.” The Messenger of Allah, peace and blessings be upon him, said:
لَا يَزَالُ لِسَانُكَ رَطْبًا مِنْ ذِكْرِ اللَّهِ
Keep your tongue moist with the remembrance of Allah.
Sunan al-Tirmidhī 3375, Grade: Sahih