“know her.” For a man to “know” a woman was a common idiom for having sexual intercourse. Sexual intercourse gives the most intimate and personal “knowledge” of the other, so “know” was used throughout the biblical world as an idiom for sexual intercourse (cp. Gen. 4:1, 17, 25; 24:16), which even included rape (Gen. 19:5; Judg. 19:25). Other idioms for sexual intercourse are, “go into” (2 Sam. 3:7), and “go near; approach” (Exod. 19:15), “uncover the nakedness” (Lev. 18:12); and sometimes “see the nakedness” (Lev. 20:17). This verse is straightforward and clear. Joseph did not have sexual intercourse with Mary until after Jesus was born, so this verse excludes any possibility that Jesus was the natural son of Joseph.