Romans 1:3

Who was made to him of the seed of David, according to the flesh. The sense is, that God promised, that he who was his true and only Son from eternity, should also become his son, as man; that the same son should be man, as well as God, when the word was made flesh, or when that divine person should be united to our human nature. Thus the same person, who was his only begotten Son from eternity, being made man, and of the seed of David, by his incarnation, was still his Son, both as God, and also as man. (Witham) --- The Greek text has not the particle ei, (to him) but only Greek: tou genomenou ek spermatos David. But St. Irenæus, (lib. iii. chap. 18.) St. Ambrose, St. Jerome read, Qui factus est ei. And also St. Augustine in his unfinished exposition of the epistle to the Romans; though before in his book against Faustus, (lib. xi. chap. 14.) he reads it otherwise. (Calmet)