(Al-Mursalath) 77 : 21
فَجَعَلْنَاهُ فِي قَرَارٍ مَكِينٍ
Then We placed it in a secure place.
“Placed it in a secure place” means “placed it in three darknesses one after another in the uterus of the mother,” as explained in verse 39: 6. “Placed it in a secure place” also means the testicles of the male, where the sperm is kept, and the loins of the female, where the ovum is kept. See explanation 23: 13.