Two elderly brothers stand before the most powerful ruler in the world, about to begin a historical mission. At this dramatic moment, the narrative pauses to record their exact ages. Noting a person's age during a major event is a common practice in biblical storytelling [קאסוטו]. For Moses, this detail highlights a massive gap in time. He originally fled Egypt as a young man, but he now returns at the age of eighty. This leaves many long years of his life completely unrecorded in the text [קאסוטו].
The primary approach among commentators is that highlighting their advanced age reveals their immense dedication. Moses and Aaron took on this heavy public burden at a time when most people are finishing their active lives. Even in that era, being in one's early eighties was considered quite old. Despite this, they acted with great energy and rushed to fulfill the will of God [ספורנו, הכתב והקבלה, ביאור שטיינזלץ]. Furthermore, their ability to receive prophecy at this stage of life points to their unique spiritual rank. Unlike other figures, Moses and Aaron are the only known prophets who continued to prophesy in their old age. This reflects their supreme level, as God spoke to them alone from a pillar of cloud [אבן עזרא, הטור הארוך].
The numbers also offer a quiet reflection on the relationship between the two brothers. Aaron was three years older, yet he showed no resentment that his younger brother was chosen to lead while he served merely as the spokesman. Detailing their exact ages emphasizes Aaron's deep humility and the perfect unity they shared. It also explains why Moses initially refused the mission, as he hesitated out of respect for his older brother [אלשיך]. When noting the timing of this event, the focus is specifically on the moment they stood and spoke together before the Egyptian king [חזקוני], with some noting it marks the very first day they addressed him [אור החיים]. The ages are linked to their confrontation with the king rather than the moment God first spoke to them, because Aaron had actually begun receiving prophecies years earlier while still in Egypt. Therefore, their ages are recorded specifically to mark their united stand before the ruler [העמק דבר].