Commentaire sur Les Psaumes 139:3

My going about and my lying down You encompassed My way, my lying down, and my dwelling You have encompassed with a wall, for I can do nothing without Your knowledge. You encompassed heb. זרית, an expression of (Exod. 25:24): “a gold crown (זר).” Menachem associated it in this manner (p. 82). Our Sages, however, interpreted it (Nid. 31a, Mid. Ps. 139:3) as referring to the droplet of [semen, transmitted in] sexual intercourse, from whose choicest part the fetus is formed, and the meaning of זֵרִיתָ (זורה) is an expression of winnowing the grain to purify it of the refuse it contains.

You are accustomed Heb. הִסכנתה, you are accustomed.