In the chaos of war, invading armies typically halt their slaughter for one of two reasons: the desire to gather loot for financial gain, or a sudden awakening of basic human compassion toward the defenseless. However, the Median and Persian forces invading Babylon operate with an entirely different, chilling brutality. Driven neither by a thirst for wealth nor possessing any natural capacity for mercy, their assault is absolute.
The destruction falls heavily upon the young men of Babylon, struck down by the weapons of the invaders. The primary approach among commentators is that the soldiers simply use their bows to shoot arrows, piercing the youth. A different perspective suggests a more close-quarters brutality, where the soldiers break into homes and use the heavy wooden bodies of the bows themselves to beat the young men to death [שד״ל]. Taking the imagery to its most terrifying extreme, another viewpoint describes the soldiers using the young victims as the actual ammunition. In this scenario, they place the youth upon the bowstrings instead of arrows, violently launching them against the ground and walls [רד״ק, אברבנאל, מלבי״ם].
The devastation extends to all stages of childhood. Some commentators view the mention of infants and young boys as a general description of the helpless youth caught in the crossfire [רד״ק, מצודת דוד, ביאור שטיינזלץ]. Others identify a specific progression of age groups: the young men represent the oldest, the infants are the fragile newborns, and the young boys are those in the middle years [אברבנאל, מלבי״ם].
The invaders' lack of humanity is expressed through two distinct emotional failures: an absence of mercy toward the infants, and a refusal to spare the young boys. Mercy is an inherent human response triggered by the suffering of the helpless, an emotion that typically moves even hardened soldiers to spare newborns. Sparing, on the other hand, is a calculated decision to avoid destroying something of practical or financial value. Ordinarily, a conquering army might spare older children to sell them into slavery for a profit. Yet, because these invaders care nothing for money, they see no financial incentive to keep the older boys alive [מלבי״ם].
Highlighting the absolute depths of this cruelty, a unique interpretation suggests that the final mention of unspared children does not refer to the Babylonian victims at all. Rather, it exposes the fundamental nature of the attackers: these soldiers are so inherently brutal that they do not even spare their own children. Consequently, there is no hope that they would ever show mercy to the children of their enemies [אברבנאל].