From Qur'an: "O believers! Remember Allah as a frequent remembrance, and glorify Him morning and evening." Al- Quran [al-Ahzaab, 33:41-42]
"Therefore, remember Me, and, I will remember you, be grateful to Me and never deny Me." Al- Quran [al-Baqarah, 2:152]
"He who turns away from the remembrance of Rahman (Allah, the Compassionate) , We assign a Satan (Shaytan) for him, who becomes his intimate companion - and turns such people away from the Right Path, while they think that they are guided aright." [az-Zukhruf - 43:36-37]
"O believers! Let neither your riches nor your children divert you from the remembrance of Allah. Those who will do so, it is they who shall be the real losers." [al-Munafiqoon - 63:9]
"Woe to those whose hearts have hardened against the Remembrance of Allah! Those are in clear error". Quran (Surah 39: Verse 22)
"Satan has mastered them and caused them to forget the Remembrance of Allah. Those are satan's party; and satan's party shall assuredly be the losers" Quran (Surah 58: Verse 19)
"They are the most wise who remember Allah, standing sitting and lying down" Quran (Surah 4: Verse 190)
"The remembrance of Allah (swt) is the greatest (deed)" Quran (Surah 29: Verse 45) What is the right definition of Remembrance of Allah?
Imam Ja'far al-Sadiq (as) said: "One of the most difficult things that Allah (SWT) has made incumbent upon his creation is the frequent remembrance of Allah. By this, I do not mean saying "SubhanaAllah" and "Alhamdulillah" and " La Ilaha Illallah" and "Allahu Akbar", though this is also part of it; what I mean is to remember Allah when faced with that which He has permitted (halal) and that which He has prohibited (haram), such that if it is an act of obedience, he carries it out immediately, and if it is an act of disobedience, he abandons it immediately" al-Kafi, v. 2, p. 65, no 4
Imam Ja'far al-Sadiq (as) narrated on the authority of his infallible forefather (as) that Prophet (saws) said: "One who obeys Allah has truly remembered Allah, even though his prayers, fasts and recitation of the Qur'an may be few in number. And he who disobeys Allah has forgotten Allah, thought his prayers, fasts and recitation of Qur'an may be abundant." Ma'ani al-Akhbar, p. 399, no 56.
Whoever Says "La Ilaha Illallah" with sincerity enters the paradise, but what is the definition of sincerity?
Actually it is part of the Remembrance of Allah (swt):
Imam Ja'far al-Sadiq (as) said: "Whoever says the phrase, "La Ilaha illallah" with sincerity will enter Paradise, and this sincerity of his should be such that "La Ilaha illallah" prevents him from all that Allah has prohibited" Ma'ani al-Akhbar, p. 370, no 1. al-Tawhid, p. 27, no. 26; Sifat al-Shi'ah, p. 5, no.6; Thawab al-A'mal, p. 19, no.1