The answer is: Ammonites

Judges 11:5

Jephthah's story is one of bravery and tragedy, serving as a powerful narrative in the Book of Judges. When the Israelites faced the Ammonites, a long-standing foe with a history of oppression, Jephthah found himself called to leadership amidst the chaos. Imagine the backdrop: Jephthah, a child of a harlot who gained his reputation perhaps not from conventional beginnings but through sheer grit and prowess as a warrior. Heandalready encountered rejection, being driven away from his family due to his mother’s background.

What's intriguing is how Jephthah’s alliance with a mixed bag of outcasts—banding together those marginalized by society—echoes a theme throughout the scriptures: that leaders often emerge from unexpected places. This places a reminder on the nature of divine authority; sometimes, it's not about one’s pedigree but one's boldness and commitment to the greater good.

Furthermore, in Judges 11, Jephthah's vow to sacrifice whatever first emerged from his house expands the narrative, highlighting the intricate relationship between promises to God and moral implications. Pledging a life, especially one close to one's heart, leads to a profound reckoning and reveals the very human capacity for regret and reflection.

Interestingly, this paradox implies that divine decisions aren't strictly formulaic but sensitive to the deeply embedded human experiences. Jephthah's encounter with the Ammonites ultimately speaks not only of conflict and victory but also serves as a cautionary tale about the weight of our vows and the complexity of human choices in matters of faith and strategy.