يٰۤـاَيُّهَا الَّذِيۡنَ اٰمَنُوا اذۡكُرُوۡا اللّٰهَ ذِكۡرًا كَثِيۡرًا O those who believe, remember Allāh abundantly. — [Qurʾān 33:41]
The instruction of remembering Allāh in abundance is given in the above verse to show gratitude for our blessings.
ʾIbn ʿAbbās raḍiyallāhu ʿanhu has stated that there is no form of worship except ذِکرُ اللہ dhikrullāh [remembrance of Allāh] for which Allāh has not fixed a limit; for example, ṣalāh is prescribed five times a day and the number of rakʿāt are determined for each ṣalāh; fasting throughout the month of Ramaḍān is determined, Ḥajj can be performed only at a particular place and at a particular time, Zakāh is prescribed once a year at a particular rate. But dhikrullāh is a form of worship for which there is no limit or defined quantity, no particular time or period, no defined posture or position, nor even the state of purity through ablution is required. Dhikrullāh is required all the time, in all circumstances, whether one is traveling or is at home, whether one is healthy or ill, whether one is on land or at sea, whether it is day or night – it is required all the time.
A Beduin said to the Prophet ṣallallāhu ʿalayhi wasallam that the number of good deeds, obligations in Islām are many; so please tell me something concise and comprehensive which I could hold on to firmly. The Prophet ṣallallāhu ʿalayhi wasallam told him,
لَا یَزَالُ لِسَانُکَ رَطْباً بِذِکْرِ اللہِ تعالیٰ “That your tongue remains always wet with the dhikr of Allāh Taʿālā.” — [Musnad Aḥmad, ʾIbn Kathīr]