Ezekiel 44:1-3 is on her perpetual virginity.
"Who is this gate (Ezekiel 44:1-4), if not Mary? Is it not closed because she is a virgin? Mary is the gate through which Christ entered this world, when He was brought forth in the virginal birth and the manner of His birth did not break the seals of virginity.” – Saint Ambrose of Milan (390AD)
“It is written (Ezekiel 44, 2): ‘This gate shall be shut, it shall not be opened, and no man shall pass through it. Because the Lord the God of Israel hath entered in by it…’ What means this closed gate in the house of the Lord, except that Mary is to be ever inviolate? What does it mean that ‘no man shall pass through it,’ save that Joseph shall not know her? And what is this – ‘The Lord alone enters in and goeth out by it,’ except that the Holy Ghost shall impregnate her, and that the Lord of Angels shall be born of her? And what means this – ‘It shall be shut for evermore,’ but that Mary is a Virgin before His birth, a Virgin in His birth, and a Virgin after His birth.” – Saint Augustine (430AD)