Genesis 7:16

ויסגור ה' בעדו AND THE LORD SHUT HIM IN — He protected him so that they could not smash up the Ark (cf. 5:13): He surrounded the Ark (thus enclosing it סגר) with bears and lions which killed some of them (Genesis Rabbah 32:8). But the literal meaning of the text is: He shut the door in front of him against the waters. Similarly, wherever בעד occurs in the Scriptures it means כנגד in front of. E. g., (20:18) “The lord had made a closure in front of (בעד) every womb”; (2 Kings 4:4) “Close the door in front of thyself (בעדך) and in front of (ובעד) thy sons”; (Job 2:4) ‘‘skin in front of (as a protection for) (בעד) skin”; (Psalms 3:4) “a shield in front of me ובעדי”: (1 Samuel 12:19) “Pray (בעד) thy servants” which means כנגד in front of (i. e. on behalf of, as a protection for) thy servants.

וְהַבָּאִ֗ים זָכָ֨ר וּנְקֵבָ֤ה מִכׇּל־בָּשָׂר֙ בָּ֔אוּ כַּֽאֲשֶׁ֛ר צִוָּ֥ה אֹת֖וֹ אֱלֹהִ֑ים וַיִּסְגֹּ֥ר יְהֹוָ֖ה בַּֽעֲדֽוֹ׃

And they that went in, went in male and female of all flesh, as God had commanded him: and the Lord shut him in.