Allah S.W.T. commends:
"Remember Me and I shall remember you. Be grateful unto Me and deny Me not."
When you remember Allah, the Creator, Sustainer and Lord of the Universe remembers you in return.
Remembrance of the Allah acts as a polish for the hearts from its rust, and causes us to be remembered by Allah S.WT.
“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 to Myself, and if he remembers me in an assembly, I mention him in an assembly better than his…”
(Bukhari and Muslim)
“Whoever comes to me walking, I go to him at speed.”
Remembrance of Allah includes specified dhikr (such as saying subhan’Allah, la ilaha ila Allah, etc.), but it is also anything you do related to Allah or mentioning Allah.
Anything that you do with Allah in mind – whether it is thinking well of Him, giving charity with the specific intention of doing it for His sake, making du’a’ (supplication) and so on is within the realm of dhikr.
Allah says :
“O son of Adam, so long as you call upon Me and ask of Me, I shall forgive you for what you have done, and I shall not mind. O son of Adam, were your sins to reach the clouds of the sky and were you then to ask forgiveness of Me, I would forgive you. O son of Adam, were you to come to Me with sins nearly as great as the earth and were you then to face Me, ascribing no partner to Me, I would bring you forgiveness nearly as great as its.” (Tirmidhi)
Finally Allah says:
“Remember Allah during times of ease and He will remember you during times of difficulty” (Tirmidhi)