Verse 5: And it was so, that when the children of Ammon made war against Israel, the elders of Gilead went to fetch Jephthah out of the land of Tob…
[So that they might fetch for their help Jephthah, לָקַ֥חַת אֶת־יִפְתָּ֖ח] So that they might take, that is, so that they might lead one taken, that is, unto Leadership. Thus in Psalm 78:70, He took from the sheepfolds, that is, unto Royal Power (Drusius).
To fetch Jephthah: By direction or instinct from God, who both qualified him for and called him to the office of a judge. See Judges 12:7; Hebrews 11:32. Otherwise they might not have chosen a bastard, Deuteronomy 23:2. Unless we will say, that there being no other person among them fit for and willing to this work, necessity dispensed with this law, as it did with other positive laws, as those of the sabbath and sacrifices.
Verse 6: And they said unto Jephthah, Come, and be our captain, that we may fight with the children of Ammon.
[Be our prince, לְקָצִין] For a prince (Jonathan, Pagnine), or, commander (Drusius). Note the expression: to be for a prince, in the place of, to be a prince. Thus, I shall be for a God, that is, I shall be God: She was to him for a wife, that is, she was to him a wife. A קָצִין is properly one that is established by the people for a time, and is below a שׁוֹטֵר/Prefect, and a Prefect below a מוֹשֵׁל/Lord. The מוֹשֵׁל is the King himself; a שׁוֹטֵר is constituted by the King, a קָצִין by the people. Those are found together in Proverbs 6:7. They are called קְצִינֵ֣י סְדֹ֑ם, rulers of Sodom, Isaiah 1:10, that is, ἄρχοντες/rulers in the Septuagint; and כָּל־קְצִינַיִךְ, all thy rulers, Isaiah 22:3 (Drusius).
Our captain: they say not our king; for the experience of Abimelech’s kingship had cooled their appetite in that particular; but our captain.
 Hebrew: וַיְהִ֕י כַּאֲשֶׁר־נִלְחֲמ֥וּ בְנֵֽי־עַמּ֖וֹן עִם־יִשְׂרָאֵ֑ל וַיֵּֽלְכוּ֙ זִקְנֵ֣י גִלְעָ֔ד לָקַ֥חַת אֶת־יִפְתָּ֖ח מֵאֶ֥רֶץ טֽוֹב׃
 Psalm 78:70: “He chose David also his servant, and took him from the sheepfolds (וַ֜יִּקָּחֵ֗הוּ מִֽמִּכְלְאֹ֥ת צֹֽאן׃)…”
 Hebrew: וַיֹּאמְר֣וּ לְיִפְתָּ֔ח לְכָ֕ה וְהָיִ֥יתָה לָּ֖נוּ לְקָצִ֑ין וְנִֽלָּחֲמָ֖ה בִּבְנֵ֥י עַמּֽוֹן׃
 For example, Genesis 17:8: “And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God (וְהָיִ֥יתִי לָהֶ֖ם לֵאלֹהִֽים׃).”
 2 Samuel 11:27: “And when the mourning was past, David sent and fetched her to his house, and she became his wife (וַתְּהִי־ל֣וֹ לְאִשָּׁ֔ה), and bare him a son. But the thing that David had done displeased the Lord.”
 Proverbs 6:7: “Which having no guide, overseer, or ruler (קָצִ֗ין שֹׁטֵ֥ר וּמֹשֵֽׁל׃)…”