וירא ראשית לו. רָאָה לִטֹּל לוֹ חֵלֶק בְּאֶרֶץ סִיחוֹן וְעוֹג, שֶׁהִיא רֵאשִׁית כִּבּוּשׁ הָאָרֶץ: וירא ראשית לו AND HE SAW THE FIRST PART FOR HIMSELF — i.e. he saw good to take for himself territory in the land of Sihon and Og, the subjugation of which was the beginning (ראשית) of the conquest of the Land,
כי שם חלקת. כִּי יָדַע אֲשֶׁר שָׁם בְּנַחֲלָתוֹ חלקת שְׂדֵה קְבוּרַת מחקק, וְהוּא מֹשֶׁה (עי' ספרי; סוטה י"ג): כי שם חלקת BECAUSE THERE WAS THE PORTION — i.e., because he knew that there in his territory was the portion of the field where was the grave of the מחקק, THE LAWGIVER, viz., Moses,
ספון. אוֹתָהּ חֶלְקָה סְפוּנָה וּטְמוּנָה מִכָּל בְּרִיָּה, שֶׁנֶּאֱמַר (דברים ל"ד) "וְלֹא יָדַע אִישׁ אֶת קְבֻרָתוֹ": ספון HIDDEN — i.e. that field was hidden and concealed from every creature, as it is said (Deuteronomy 34:6) “And no man knows his burial place” (Sifrei Devarim 355:6).
ויתא. גָּד: ויתא AND HE CAME — i.e. Gad came.
ראשי עם. הֵם הָיוּ הוֹלְכִין לִפְנֵי הֶחָלוּץ בְּכִבּוּשׁ הָאָרֶץ, לְפִי שֶׁהָיוּ גִּבּוֹרִים, וְכֵן הוּא אוֹמֵר "וְאַתֶּם תַּעַבְרוּ חֲמֻשִׁים לִפְנֵי אֲחֵיכֶם וְגוֹ'" (יהושע א'): ראשי עם AT THE HEAD OF THE PEOPLE — They (the men of Gad) marched before the armed men at the conquest of the Land, because they were mighty, and thus does it state that Joshua said to them, (Joshua 1:14) “Ye shall pass armed before your brethren, etc.”.
צדקת ה' עשה. שֶׁהֶאֱמִינוּ דִבְרֵיהֶם וְשָׁמְרוּ הַבְטָחָתָם לַעֲבֹר אֶת הַיַּרְדֵּן עַד שֶׁכָּבְשׁוּ וְחָלְקוּ; דָּ"אַ — ויתא מֹשֶׁה ראשי עם, צדקת ה' עשה עַל מֹשֶׁה אָמוּר (עי' ספרי): צדקת ה' עשה HE DID THE RIGHTEOUSNESS OF THE LORD — because they proved true to their word and kept their promise to cross the Jordan and to remain there until they (the Israelites) had conquered it and divided it amongst the tribes. — Another explanation: ויתא AND HE — the Lawgiver, Moses — CAME ראשי עם AT THE HEAD OF THE PEOPLE, צדקת ה' עשה HE DID THE RIGHTEOUSNESS OF THE LORD — This, too, is spoken of Moses (cf. Sifrei Devarim 355:9).