10 Therefore since heart is put for desire, and eyes for sight, and hands for work achieved—and yet, without in any way being made up of parts, God desires and foresees and acts, these same operations being expressed by the words heart, and eyes, and hand—is not the meaning of the phrase that He begot from the womb an assertion of the reality of the birth? Not that He begot the Son from His womb, just as neither does He act by means of a hand, nor see by means of eyes, nor desire by means of a heart. But since by the employment of these terms it is made clear that He really acts and sees and wills everything, so from the word 'womb' it is clear that He really begot from Himself Him Whom He begot; not that he made use of a womb, but that He purposed to express reality. Just in the same way He does not will or see or act through bodily faculties, but uses the names of these members in order that through the services performed by corporeal forces we may understand the power of forces which are not corporeal.
Source: On the Trinity (New Advent)