וּנְתָנָ֛הּ יְהוָ֥ה אֱלֹהֶ֖יךָ בְּיָדֶ֑ךָ וְהִכִּיתָ֥ אֶת־כָּל־זְכוּרָ֖הּ לְפִי־חָֽרֶב׃
And when the LORD thy God delivereth it into thy hand, thou shalt smite every male thereof with the edge of the sword;
Rashi on Deuteronomy
ונתנה ה' אלהיך בידך means THEN THE LORD THY GOD WILL GIVE IT INTO THY HANDS — if you have done all that is prescribed in this section the Lord will in the end give it into your hands (Sifrei Devarim 200:6).