“Mt 1:25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.”
It’s also worth noting the “till” in that sentence. This usage plainly states that after she bore Jesus, Joseph did “know” her. If the word “before” had been used, we couldn’t make that conclusion, but with “till”, there is no other way to read it.
And Michal the daughter of Saul had no child till the day of her death. (2 Samuel 6:23)This usage plainly states that after the day of her death, Michal did "have a child". If the word “before” had been used, we couldn’t make that conclusion, but with “till”, there is no other way to read it.