Here is something you will do tonight that you cannot actually decide to do. You can lie down, close your eyes and slow your breathing, but the moment of falling asleep happens to you. One second you are thinking about tomorrow, and the next you are gone, for hours, with no idea where you were.
Then, in the morning, you come back. Your name, your memories, your worries, your face in the mirror. We do this about 25,000 times in a lifetime and hardly ever ask how strange it is. The Qur'an asks. It calls sleep a small death, and waking a gift.
“Allah receiveth (men's) souls at the time of their death, and that (soul) which dieth not (yet) in its sleep. He keepeth that (soul) for which He hath ordained death and dismisseth the rest till an appointed term. Lo! herein verily are portents for people who take thought.”
Qur'an 39:42 · Pickthall (1930)
This verse is in Surah al-Zumar (The Groups). The Arabic verb, yatawaffā, means to take something back in full, as a debt is repaid. Here it covers both death and sleep: every night, God takes the self, and every morning He returns it, except for the night He does not. Other verses call sleep a rest (78:9) and one of God's signs (30:23). And 6:60 says, 'He it is who takes you by night, and knows what you did by day.'
What science shows
Sleep is not switching off. Through the night the brain moves in cycles of roughly 90 minutes through lighter sleep, deep slow-wave sleep and REM (rapid eye movement) sleep, when most vivid dreams happen. Adults need around 7 to 9 hours a night, according to the NHS, and teenagers need more. If you live to 75, you will spend about 25 of those years asleep.
What is it for? Scientists are still not completely sure, and that itself is remarkable. One strong idea is cleaning. In 2013 a team led by Maiken Nedergaard reported in Science that in sleeping mice the spaces between brain cells widened by about 60 percent. That lets fluid wash through and carry away waste, including a protein linked to Alzheimer's disease. Whether the same happens in the same way in humans is still being studied.
Another is memory. A major review in Nature Reviews Neuroscience (Diekelmann and Born, 2010) brought the evidence together. During sleep, it found, the brain replays and strengthens what it learned during the day, and sorts what to keep. That is why revising and then sleeping usually works better than staying up all night.
Sleep is also ancient. In 2017 researchers showed that the upside-down jellyfish Cassiopea, which has no brain at all, has a sleep-like state at night. It pulses more slowly, responds less, and if kept awake, is sluggish the next day (Nath and colleagues, Current Biology). Almost every animal studied, from fruit flies to whales, needs some form of sleep.
So every night every one of us does something we cannot control, do not fully understand, and cannot live without. We let go, and something we did not earn returns us. The verse does not explain sleep. It asks us to notice what kind of gift it is.
What each faith says
Judaism
“Into Thy hand I commit my spirit; Thou hast redeemed me, O LORD, Thou God of truth.”
Psalm 31:6 · JPS 1917
The Talmud says, 'Sleep is one-sixtieth of death' (Berakhot 57b), a small taste of it. Jewish prayer treats each night as a handing over. Before sleep many Jews say the bedtime Shema, the declaration of faith that begins “Hear, O Israel”. The hymn Adon Olam, “Lord of the World”, sung in synagogues every week, ends: 'Into His hand I commit my spirit, when I sleep and when I wake; and with my spirit, my body too: the LORD is with me, I shall not fear.' The line comes from Psalm 31.
In the morning the first words are Modeh Ani: thanks to God 'for You have returned my soul to me with compassion'. The Psalms put the trust simply: 'In peace will I both lay me down and sleep; for Thou, LORD, makest me dwell alone in safety' (Psalm 4:9). Psalm 127 adds that God 'giveth unto His beloved in sleep', a reminder that rest is a gift, not a failure.
Christianity
“But we don't want you to be ignorant, brothers, concerning those who have fallen asleep, so that you don't grieve like the rest, who have no hope.”
1 Thessalonians 4:13 · WEB
Psalm 31 is heard at the most important moment of the Christian story. On the cross, Jesus, as the Gospel of Luke tells it, 'crying with a loud voice, said, Father, into your hands I commit my spirit'. Then he breathed his last. In Compline, the night prayer kept in monasteries and in many Catholic and Anglican parishes, Christians still say that verse before sleep: 'Into your hands, Lord, I commend my spirit.'
The New Testament also uses sleep as a gentle word for death. When his friend Lazarus dies, Jesus says, 'Our friend, Lazarus, has fallen asleep, but I am going so that I may awake him' (John 11:11). Paul writes to grieving Christians about 'those who have fallen asleep' and tells them not to grieve 'like the rest, who have no hope'. Christians believe God will raise the dead as surely as morning follows night.
Islam
“In Your name, my Lord, I lay down my side, and by You I raise it. If You keep my soul, have mercy on it; and if You send it back, protect it as You protect Your righteous servants.”
Bukhari 6320 · our rendering
Muslims are taught to go to sleep, and wake up, with words that come straight from this verse. Muhammad ﷺ (peace be upon him) would lie on his right side and say: 'In Your name, my Lord, I lay down my side, and by You I raise it. If You keep my soul, have mercy on it; and if You send it back, protect it as You protect Your righteous servants' (Bukhari 6320). On waking, he said: 'Praise be to God, who gave us life after He had given us death, and to Him is the return' (Bukhari 6312).
The classical scholar al-Rāghib al-Iṣfahānī was an expert on the Qur'an's vocabulary who died around 1108. He put it in a phrase: 'sleep is a light death, and death is a heavy sleep.' So each night is a rehearsal, and each morning a small resurrection. The verse ends 'for a people who reflect', and that is the invitation. We are to treat waking up not as automatic but as being sent back, with a day we did not have to be given.
Same and different
All three traditions treat sleep as a small death and waking as a return given by God. Each hands the soul over at night with words of trust, and Jews and Christians even use the same verse from Psalm 31. Islam is the one that names death and sleep with a single verb, yatawaffā, as if both were God taking the soul back in full. They differ on what the picture points to. For Jews, it points to God's faithful care day by day and the hope of the world to come. For Christians, sleep is a picture of death in the light of Christ's resurrection. For Muslims, it is God taking and returning the soul each night until the night He keeps it.
A moment to reflect
- How does it feel to think of falling asleep as letting go?
- What do you say, or think, just before you sleep and just after you wake?
- What helps you let go at the end of a day?
- If every morning were treated as a gift, what would you do with today?
Watch
A clear walk through the stages of a night's sleep.
A TED-Ed animation on what sleep does for the brain and body.
The Royal Institution on why we sleep and how the body clock works.
Sleep scientist Matt Walker on what we lose when we cut sleep short.
Do it together
Bring the bedtime and waking prayers of each tradition: Adon Olam's last verse, the Compline line from Psalm 31, and the duas from Bukhari 6312 and 6320. Read them side by side and notice what each asks for.
For one week, everyone in the family or class notes when they went to sleep, when they woke and how they felt. Compare with the NHS guidance and talk about one small change to try.
Pick one evening a week with no screens for the last hour before bed. Use the time to read, talk, or say a goodnight prayer or thought together.
Go deeper
- Qur'an 39:42 with translations · scripture
- Psalm 31 (JPS 1917) on Sefaria · scripture
- 1 Thessalonians 4 (WEB) on Bible Gateway · scripture
- Sahih al-Bukhari 6320 on Sunnah.com · scripture
- NHS: sleep and tiredness · article
In pictures
Try this · KS2 · 1 week, 2 min a day · Science
My sleep diary
You need: a notebook or the printable diary
- Each night write down the time you go to bed.
- Each morning write the time you wake and how you feel, from 1 to 5.
- After a week, add up your hours of sleep each night.
- Is there a pattern between sleep and how you feel?
Every night we let go of everything and trust that we will wake: three faiths say words of thanks as they do it.
Sources (5)
- Adults need around 7 to 9 hours of sleep: NHS, Sleep and tiredness
- Natural sleep is associated with a 60% increase in interstitial space and faster clearance of beta-amyloid in mice: Xie et al., Science, 2013
- Sleep supports memory consolidation: Diekelmann & Born, Nature Reviews Neuroscience, 2010
- Brainless jellyfish Cassiopea shows a sleep-like state: Nath et al., Current Biology, 2017
- Al-Rāghib: sleep is a light death and death a heavy sleep: al-Rāghib, Mufradāt, s.v. nawm