Sefer Yehoshua chapter one verse 13 reads:
זָכוֹר֙ אֶת־הַדָּבָ֔ר אֲשֶׁ֨ר צִוָּ֥ה אֶתְכֶ֛ם מֹשֶׁ֥ה עֶֽבֶד־יְהוָ֖ה לֵאמֹ֑ר יְהוָ֤ה אֱלֹהֵיכֶם֙ מֵנִ֣יחַ לָכֶ֔ם וְנָתַ֥ן לָכֶ֖ם אֶת־הָאָ֥רֶץ הַזֹּֽאת
On this Radak writes
זכור: מקור.
What does he mean by מקור?
All classic rabbinic uses or similarities to this word make no sense in this context: Source. Womb. Passive version of cold?! Everything seems patently wrong. I even checked Radak's own Seffer Hashorashim to see if he gave the word any special meaning. No luck.