Jesus answered: `Even so I tell you that ye ought to watch with the soul by the sun of justice [which is] our God, and not to boast yourselves of the watchings of the body. It is most true, therefore, that bodily sleep is to be a voided as much as is possible, but [to avoid it] altogether is impossible, the sense and the flesh being weighed down with food and the mind with business. Wherefore let him that will sleep little avoid too much business and much food.
`As God liveth, in whose presence standeth my soul, it is lawful to sleep somewhat every night, but it is never lawful to forget God and his fearful judgement: and the sleep of the souls is such oblivion.'
Then answered he who writeth: `O master, how can we always have God in memory? Assuredly, it seemeth to us impossible.'
Said Jesus, with a sigh: `This is the greatest misery that man can suffer, O Barnabas. For man cannot here upon earth have God his creator always in memory; saving them that are holy, for they always have God in memory, because they have in them the light of the grace of God, so that they cannot forget God. But tell me, have ye seen them that work quarried stones, how by their constant practice they have so learned to strike that they speak with others and all the time are striking the iron tool that worketh the stone without looking at the iron, and yet they do not strike their hands? Now do ye likewise. Desire to be holy if ye wish to overcome entirely this misery of forgetfulness. Sure it is that water cleaveth the hardest rocks with a single drop striking there for a long period.
`Do ye know why ye have not overcome this misery? Because ye have not perceived that it is sin. I tell you then that it is an error, when a prince giveth thee a present, O man, that thou shouldst shut thine eyes and turn thy back upon him.
Even so do they err who forget God, for at all times man receiveth from God gifts and mercy.'
An Islamic Perspective and Commentary
Remembrance of God is also stressed in Quran in numerous verses. Just like Jesus (peace be upon him) talks above about sleeping less, and remembering God during night, the Qur'an instructs prophet Muhammad, and the believers in his example, to pray during night:
Stand (to prayer) by night, but not all night,-
and to remember God whole-heartedly:
But keep in remembrance the name of thy Lord and devote thyself to Him whole-heartedly.
The Qur'an also mentions that there are among the People of the Book (includes Jews and Christians) who do stand up during the night, and remember God:
3:113 Not all of them are alike: Of the People of the Book are a portion that stand (For the right): They rehearse the Signs of God all night long, and they prostrate themselves in adoration.
According to Qur'an, Remembrance of God is the greatest (thing in life):
29:45 Recite what is sent of the Book by inspiration to thee, and establish regular Prayer: for Prayer restrains from shameful and unjust deeds; and remembrance of God is the greatest (thing in life) without doubt. And God knows the (deeds) that ye do.
and believers are expected to remember God virtually all the time:
while standing, sitting, and lying down on their sides:
3:191 Men who celebrate the praises of God, standing, sitting, and lying down on their sides, and contemplate the (wonders of) creation in the heavens and the earth, (With the thought): "Our Lord! not for naught Hast Thou created (all) this! Glory to Thee! Give us salvation from the penalty of the Fire.
when Satan assaults them:
7:201 Those who fear God, when a thought of evil from Satan assaults them, bring God to remembrance, when lo! they see (aright)!
when they face a difficulty:
8.45 O ye who believe! When ye meet a force, be firm, and call Allah in remembrance much (and often); that ye may prosper:
when they want the satisfaction of their heart:
13:28 "Those who believe, and whose hearts find satisfaction in the remembrance of God: for without doubt in the remembrance of God do hearts find satisfaction.
often, morning and evening:
33:41-42 O ye who believe! Celebrate the praises of God, and do this often; And glorify Him morning and evening.
As Jesus (peace be upon him) calls forgetting God a sin, the Qur'an talks about the consequences of forgetting God:
059.019 And be ye not like those who forgot Allah; and He made them forget their own souls! Such are the rebellious transgressors!
009.067 ...They have forgotten Allah; so He hath forgotten them.
43:36 If anyone withdraws himself from remembrance of (God) Most Gracious, We appoint for him an evil one, to be an intimate companion to him.
39:22 ... Woe to those whose hearts are hardened against celebrating the praises of God! they are manifestly wandering (in error)!
63:9 O ye who believe! Let not your riches or your children divert you from the remembrance of God. If any act thus, the loss is their own.
We also find in Qur'an the equivalent of "for at all times man receiveth from God gifts and mercy"
014.034 And He giveth you of all that ye ask for. But if ye count the favours of Allah, never will ye be able to number them. Verily, man is given up to injustice and ingratitude.
The following verse summarizes it all:
2:152 Then do ye remember Me; I will remember you. Be grateful to Me, and reject not Faith.