The answer is: 20

Numbers 1:3

When we think of age thresholds, it's fascinating to realize that at the age of 20, young individuals in Israel were seen as ready to take on the responsibility of war. This can give us a glimpse into the culture of ancient Israel, which viewed 20 as a significant transition point from adolescence into mature adulthood, reflecting a more severe approach to life's big responsibilities.

It's not just a number—ages in the Bible often carried symbolic meanings. For instance, 20 years holds significance in other passages too, like overlapping age thresholds for service in the Temple. Similarly, when Jesus began His ministry around the age of 30, it aligned with figures who held significant positions, such as priests or kings, emphasizing the point where maturity and responsibility converged.

Looking further back, our minds may also wander to another 20-year footnote: it's about when Moses began leading the Israelites, marking a critical phase in their journey to the Promised Land. Even on a historical note, did you know that ancient warriors often had to prove themselves in battle by the time they reached manhood? Fighting was as much about survival as it was about heritage, so stepping into battle at such an age helped forge not only individual identities but the collective identity of the entire Israelite nation. Life at its core is about forming connections with others as they support each other through every challenge; even the colorful community of Israel shows how war shaped unity and identity long before modern times.