Allah commands His believing servants to remember their Lord much, Who has bestowed upon them all kinds of blessings and favors, because this will bring them a great reward and a wonderful destiny. Imam Ahmad recorded that `Abdullah bin Busr said: "Two bedouins came to the Messenger of Allah and one of them said: `O Messenger of Allah, which of the people is best' He said:
«مَنْ طَالَ عُمْرُهُ وَحَسُنَ عَمَلُه»
(The one whose life is long and whose deeds are good.) The other one said: `O Messenger of Allah, the laws of Islam are too much for us. Teach me something that I can adhere to.' He said,
«لَايَزَالُ لِسَانُكَ رَطْبًا بِذِكْرِ اللهِ تَعَالَى»
(Keep your tongue moist with the remembrance of Allah, may He be exalted.) At-Tirmidhi and Ibn Majah recorded the second part of this report. At-Tirmidhi said, "This Hadith is Hasan Gharib''. Imam Ahmad recorded that `Abdullah bin `Amr, may Allah be pleased with him, said that the Messenger of Allah said,
«مَا مِنْ قَوْمٍ جَلَسُوا مَجْلِسًا لَمْ يَذْكُرُوا اللهَ تَعَالَى فِيهِ إِلَّا رَأَوْهُ حَسْرَةً يَوْمَ الْقِيَامَة»
(No people sit together without mentioning Allah, but they will see that as regret on the Day of Resurrection.) `Ali bin Abi Talhah reported that Ibn `Abbas, may Allah be pleased with him, commented on the Ayah:
﴿اذْكُرُواْ اللَّهَ ذِكْراً كَثِيراً﴾
(Remember Allah with much remembrance. ) "Allah did not enjoin any duty upon His servants without setting known limits and accepting the excuses of those who have a valid excuse -- apart from Dhikr, for Allah has not set any limits for it, and no one has any excuse for not remembering Allah unless he is oppressed and forced to neglect it. Allah says:
﴿فَاذْكُرُواْ اللَّهَ قِيَـماً وَقُعُوداً وَعَلَى جُنُوبِكُمْ﴾
(Remember Allah standing, sitting down, and (lying down) on your sides) (4:103). By night and by day, on land and on sea, when traveling and when staying home, in richness and in poverty, in sickness and in health, in secret and openly, in all situations and circumstances. And Allah says:
﴿وَسَبِّحُوهُ بُكْرَةً وَأَصِيلاً ﴾
(And glorify His praises morning and Asila.) If you do this, He and His angels will send blessings upon you.'' There are very many Ayat, Hadiths and reports which encourage the remembrance of Allah, and this Ayah urges us to remember Him much. People such as An-Nasa'i and Al-Ma`mari and others have written books about the Adhkar to be recited at different times of the night and day.
﴿وَسَبِّحُوهُ بُكْرَةً وَأَصِيلاً ﴾
(And glorify His praises morning and Asila) in the morning and in the evening. This is like the Ayah:
﴿فَسُبْحَانَ اللَّهِ حِينَ تُمْسُونَ وَحِينَ تُصْبِحُونَ - وَلَهُ الْحَمْدُ فِى السَّمَـوَتِ وَالاٌّرْضِ وَعَشِيّاً وَحِينَ تُظْهِرُونَ ﴾
(So glorify Allah, when you come up to the evening, and when you enter the morning. And His are all the praises and thanks in the heavens and the earth; and in the afternoon and when you come up to the time, when the day begins to decline.) (30:17-18).
﴿هُوَ الَّذِى يُصَلِّى عَلَيْكُمْ وَمَلَـئِكَتُهُ﴾
(He it is Who sends Salah on you, and His angels too,) This is encouragement to remember Allah, i.e., He will remember you, so remember Him. This is like the Ayah:
﴿كَمَآ أَرْسَلْنَا فِيكُمْ رَسُولاً مِّنْكُمْ يَتْلُواْ عَلَيْكُمْ آيَـتِنَا وَيُزَكِّيكُمْ وَيُعَلِّمُكُمُ الْكِتَـبَ وَالْحِكْمَةَ وَيُعَلِّمُكُم مَّا لَمْ تَكُونُواْ تَعْلَمُونَ - فَاذْكُرُونِى أَذْكُرْكُمْ وَاشْكُرُواْ لِي وَلاَ تَكْفُرُونِ ﴾
(Similarly, We have sent among you a Messenger of your own, reciting to you Our Ayat and purifying you, and teaching you the Book and the Hikmah, and teaching you that which you used not to know. Therefore remember Me. I will remember you, and be grateful to Me and never be ungrateful to Me) (2:151-152) The Prophet said:
«يَقُولُ اللهُ تَعَالَى: مَنْ ذَكَرَنِي فِي نَفْسِهِ ذَكَرْتُهُ فِييَنفْسِي، وَمَنْ ذَكَرَنِي فِي مَلَإٍ ذَكَرْتُهُ فِي مَلَإٍ خَيْرٍ مِنْه»
(Allah says: "Whoever remembers Me to himself, I will remember him to Myself, and whoever remembers Me in a gathering, I will remember him in a better gathering.'')