Exodus 32:35Meaning & Commentary from the Church Fathers

The Lord struck the people for their transgression regarding the idol that Aaron had fashioned. What clearer demonstration of divine judgment upon wrongdoers could there be than the swift retribution faced by those who sinned? Yet, when the entirety of the people stood under condemnation, why did the consequences not extend to everyone? This must be understood: the merciful Lord inflicted His sword upon a portion of the people, so that the remainder could learn from their example and be instructed, all while maintaining His righteousness and revealing His mercy. For the punishment displayed His severity, while His compassion was evident in the sparing of others, with both attributes presented in an imbalanced scale—wherein mercy prevailed over judgment.

An evidence of the downfall of the three thousand is found in verse 28.