Theodoret of Cyrus
The phrase to be at the forefront and not at the rear suggests leadership rather than being in a subordinate position. This is further emphasized by the addition that you will be exalted and not held down.
And the Lord shall make thee the head and not the tail: and thou shalt be always above, and not beneath: yet so if thou wilt hear the commandments of the Lord thy God which I command thee this day, and keep and do them,
וּנְתֽ͏ָנְךָ֨ יְהוָ֤ה לְרֹאשׁ֙ וְלֹ֣א לְזָנָ֔ב וְהָיִ֙יתָ֙ רַ֣ק לְמַ֔עְלָה וְלֹ֥א תִהְיֶ֖ה לְמָ֑טָּה כִּֽי־תִשְׁמַ֞ע אֶל־מִצְוֺ֣ת ׀ יְהוָ֣ה אֱלֹהֶ֗יךָ אֲשֶׁ֨ר אָנֹכִ֧י מְצַוְּךָ֛ הַיּ֖וֹם לִשְׁמֹ֥ר וְלַעֲשֽׂוֹת׃
One Church Father comments on this verse
The phrase to be at the forefront and not at the rear suggests leadership rather than being in a subordinate position. This is further emphasized by the addition that you will be exalted and not held down.
Passages read together with this verse.