"O you who believe! Celebrate the praises of Allah, and do so often; and glorify Him morning and evening." (Holy Qur'an 33:41-41)
Allah (SWT) has commanded us to remember him always. He says: "Remember Me, I shall remember you." (Qur'an 2:152) Thus it is very important for us, as Muslims, to perform dhikr, or remembrance, of Allah (SWT).
The purpose of dhikr is to purify our hearts and souls and uplift our spirits. All words of praise and glory to Allah (SWT), whether spoken out loud, or silently in one's heart, are known as dhikr. When people do dhikr, their hearts turn to the highest ideals and are free from the temptations of sin. Obviously this is true only if the words come from the heart and not just from the tongue.
The Qur'an says:
"And establish regular prayer, for prayer restrains from shameful and unjust deeds, and remembrance of Allah is the greatest thing in life, without doubt." (Surah al-Ankabut 29:45)
In other words, dhikr has an even greater impact in protecting us from shameful and unjust deeds than regular prayers do. This is because when a person opens his heart to Allah (SWT) and utters words in His praise, Allah (SWT) fills him with strength and inner peace, comforting his minds and his heart. The Prophet (PBUH) once said, "When any group of men remember Allah, angels surround them and mercy covers them, tranquillity descends upon them, and Allah mentions them to those who are with Him." (Reported by Abu Hurairiah)
The Prophet (PBUH) has described many forms of dhikr and their importance. Among them is what is described in this hadith: "And whoever says subhan Allah wa bihamdihi (Glorified is Allah with all praise due to Him) a hundred times during a day, will have all sins wiped off even if they were as numerous as the foam on the surface of the sea." (Narrated by Abu Hurairiah) The Prophet (PBUH) has also said, "When a servant of Allah utters the words la ilaha illa'Allah (there is none worthy if worship except Allah (SWT)) sincerely, the doors of heaven open up for these words until they reach the Throne of Allah, so long as it utterer keeps away from the major sins." (Reported by Abu Hurairiah) It is better to count the phrases on the fingers than counting beads because the fingers will be questioned and will speak on your behalf on the Day of Judgment.
The Prophet SAW said, "The contrast between a person who glorifies Allah and one who does not remember Him is like that between the living and the death." One who does not remember Allah, though he may be alive physically, he is dead spiritually and his life is but worthless. When one keeps away from the remembrance of Allah, Shaytaan becomes his remembrance and guidance (to Hell).
Dhikr has been given much importance in Islam, and thus it is better to follow a certain etiquette of dhikr. One should face the Ka'bah when doing dhikr, for the best assemblies are those that are facing the qiblah. There is a verse in the Qur'an which implies that it is preferable to do dhikr in silence rather than out loud; the verse says: "And do bring your Lord to remembrance in your very soul, with the humility and in reverence, without loudness in words, in the morning and evening, and be not of those who are unheedful." (7:205) The Prophet (PBUH) once happened upon a group of Muslims doing dhikr out loud. He then said, "Give yourselves a respite, you are not calling upon someone deaf or absent. Surely He Whom you are calling upon is near you and He listens to all." This hadith also emphasizes the love and closeness to Allah (SWT) that a person should feel when doing dhikr.
Doing dhikr in a group is even better than doing it by oneself. Ibn Umar has narrated that "The Prophet, peace be upon him, said, 'When you pass by a garden of Paradise, avail yourselves to it.' The companions asked, 'What are the gardens, O Messenger of Allah?' The Prophet, peace upon him, replied "The assemblies or circles of dhikr. There are some angels of Allah who go about looking for such assemblies of dhikr, and when they find them they surround them.'" Often times people gather in a group and talk about trivial and irrelevant matters. Participating in such vain conversations is clearly looked down upon in Islam. Therefore, we should constantly remember Allah (SWT) and do dhikr. The Prophet (PBUH) said: "If people sit in an assembly in which they do not remember Allah nor invoke blessing on the Prophet, it will be a cause of grief for them on the Day of Judgment." (Narrated by Abu Hurairiah)
In conclusion, to feel the importance and see the benefits of dhikr, this hadith has been provided: The Prophet narrated: "Allah (SWT) says: 'I am to my servant as he expects of Me, I am with him when he remembers Me. If he remembers Me in his heart, I remember him in My heart, and if he remembers Me in an assembly, I mention him in an assembly better than his, and if he draws nearer to Me a hand's span, I draw nearer to him an arm's length, and if he comes to me walking I come to him running."