يُولِجُ ٱلَّيْلَ فِى ٱلنَّهَارِ وَيُولِجُ ٱلنَّهَارَ فِى ٱلَّيْلِ ۚ وَهُوَ عَلِيمٌۢ بِذَاتِ ٱلصُّدُورِ
Yūliju'l-layla fi'n-nahāri wa yūliju'n-nahāra fi'l-layl, wa huwa ʿalīmun bi-dhāti'ṣ-ṣudūr "He makes the night enter into the day and makes the day enter into the night. He is the Knower of what is in the breasts."
- ولج (walaja) — he went in
- وليجة (walīja) — a person who has slipped into a group from outside, who has got in among them; a confidant. It occurs in the Qurʾān: "…those who have taken no walīja apart from God, His Messenger and the believers" (al-Tawba 9/16). There the word means "an outsider slipped into the inner circle".
- ولج (walaj) — a cleft in a road, a hollow in a rock
The picture the root carries is this: not passing through a wide opening but seeping through a narrow gap. A thing entering inside another thing, into a place that does not belong to it.
The verb in the verse is in the إفعال (ifʿāl) form: walaja (he entered) → awlaja (he made enter). That is, it has been made transitive. The night does not enter of itself; it is made to enter.
The best-known use of this root in the Qurʾān is the expression "He knows what enters the earth" in the previous verse of this same sūra (57/4). The same root, two verses apart, once in the context of knowledge and once in the context of an act.
The sentence is two-directional and symmetrical: night into day, day into night. The same verb, twice, with its objects exchanged.
As to what is being described there are several readings in the classical commentaries, and all of them point to concrete events:
| Reading | Explanation |
|---|---|
| The changing length of the seasons | In one half of the year the day lengthens and the night shortens; in the other half the reverse. What is taken from one is added to the other. |
| Dawn and twilight | The edge of the night mingles with the day and the edge of the day with the night; there is no sharp boundary between the two. |
| Both | The word answers to both phenomena |
The word itself suits the third reading better. For īlāj describes not a sharp exchange of places but a seeping. The night does not take the day's place; it enters into it.
And this genuinely fits the phenomenon itself. The turning of day into night is not an instantaneous event; dawn and dusk are transitional zones in which the two states mingle. In the same way the change in the length of the seasons is not by leaps but by a shift of a few minutes from day to day.
A note is needed here: this is an agreement with observation, not a claim of scientific miracle. That the change from night to day is gradual is something that can be seen with the naked eye, and those addressed by the verse saw it too. What the verse does is to name a phenomenon everyone sees with exactly the right word.
All three describe the passing of opposites into one another. Life and death, descent and ascent, night and day. And the four names in the third verse were opposite pairs too: first-last, outer-inner.
This is the structure repeated across the first six verses of the sūra: the gathering of opposites into a single hand.
What this is a preparation for will be seen in the seventh verse. The sūra will ask the one addressed to give what is in his hand. And the greatest obstacle to the act of giving is the human assumption that "what is in my hand is mine". The first six verses dismantle this assumption systematically, without issuing a single command.
ذات الصدور — literally "that which the breasts possess", that is, what is in the breasts, the contents of the breast.
صدر — root ص-د-ر: the front or upper part of a thing, the place from which it issues. From the same root come ṣudūr (to issue forth), maṣdar (a source, a place of issuing), ṣadāra. Ṣadr is the front part of the body — the breast.
In Arabic ṣadr is mostly named as the seat of the feelings, of intention and of hidden thoughts; qalb, rather, as the seat of apprehension and decision. The distinction is not absolute and there is no unified description in the sources.
That this sentence should be placed here is striking. The verse had been speaking of night and day — the largest-scale and most visible rhythm of the universe. And the sentence closes with the most hidden thing in a human being's breast.
This is the same movement as the close of the fourth verse: a descent from the cosmic scale to the personal. But here a further step is taken — there it said "what you do" (visible acts), here "what is in the breasts" (unseen intentions).
And considering what follows in the sūra this is entirely apt. The sūra will ask for spending; spending is a visible act. But the sūra will also speak of the hypocrites — that is, of those who perform the same act outwardly while being otherwise within. The scene in the thirteenth verse is built on exactly this.
The close of the sixth verse prepares that scene six verses in advance: what cannot be told apart when looked at from outside can be told apart when looked at from here.
A further link is also made with the third verse. There God was named al-Bāṭin — the one who is innermost. Here what He knows is the inside of the breasts. Name and act are matched three verses apart.