There are many hadith mentioning the virtues of remembrance of Allah. Among them is the saying of the Prophet (alaihi wa sal-lam), “Shall I tell you about the best among all your deeds, the purest in the estimation of your King, the highest of your deeds in status, which is better for you than spending gold and silver, and is better for you than encountering your enemies and striking their necks and them striking yours?”
The Companions said, “Yes, indeed inform us, O Messenger of Allah!” The
Prophet (PBUH) said, “(It is) the remembrance of Allah.” (at-Tirmidhi).
He (PBUH) also said, “The similitude of the one who remembers his Lord and the one who does not remember his Lord is like the living and the dead respectively.” (al-Bukhari).
He sai m) said as well, “Allah ( PBUH ) says, ‘I am as My servant thinks of Me, and I am with him when he remembers Me. If he remembers Me in himself, I remember him in Myself. If he remembers Me in a company, I remember him in a company better than his company. If he comes one handspan nearer to Me, I come one cubit nearer to him.” (al-Bukhari).
He (PBUH) also said, “The mufarridoon have come ahead of other people.
The Companions said, “Who are the mufarridoon, O Messenger of Allah?” He
alaihi wa sallam) said, “Those men and women that remember Allah with much remembrance.” (Muslim).
He also gave the following advice to one of the companions saying, “Let your tongue remain moist constantly in the remembrance of Allah.” (at-Tirmidhi).
And there are many more hadith encouraging the remembrance of Allah, (018).
Multiplication of the rewards:
The rewards of good deeds are multiplied just as the reward of reciting the Qur’an is multiplied, and this occurs according to:
1) What is in the heart of a
person, his faith and sincerity, love for Allah and what flows from this;
2) The contemplation of the heart in remembering Allah and preoccupation with this, making the remembrance not simply by the tongue alone.
Whoever fulfills these two conditions, will have Allah expiate his sins and give him his full reward.
As for he who is deficient in these matters, then the expiation of sins and the reward will be in accordance with his deficiency.
Source: Tefseer Ushr l akr