The Enarrations, or Expositions, on the Psalms

¹⁰ But this is put off, this will be granted afterwards: what is there now? “From the womb I have begotten You, before the morning star.” What is here? If God has a Son, has He also a womb? Like fleshly bodies, He has not; for He has not a bosom either; yet it is said, “He who is in the bosom of the Father, has declared Him.” But that which is the womb, is the bosom also: both bosom and womb are put for a secret place. What means, “from the womb”? From what is secret, from what is hidden; from Myself, from My substance; this is the meaning of “from the womb;” for, “Who shall declare His generation?” Let us then understand the Father saying unto the Son, “From My womb before the morning star have I brought You forth.”

What then means, “before the morning star”? The morning star is put for the stars, as if the Scripture signified the whole from a part, and from one conspicuous star all the stars. But how were those stars created? “That they may be for signs, and for seasons, and for days, and years.”...This expression also, “before the morning star,” is used both figuratively and literally, and was thus fulfilled. For the Lord was born at night from the womb of the Virgin Mary; the testimony of the shepherds does assert this, who were “keeping watch over their flock.” So David: O Thou, my Lord, who sittest at the right hand of my Lord, whence are You my Son, except because, “From the womb before the morning star I have begotten You”?