Why did the Prophet (peace and blessings be upon him) command him to take back his divorced wife while she was menstruating and to wait until she became pure, then menstruated again, then became pure, instead of commanding him to divorce her immediately upon her purity during which he had not consummated the marriage with her?

Scholars have differed regarding the wisdom behind the command for a divorcer to keep his wife until she purifies, then menstruates, then purifies again. Some say it is to ensure her womb is clear before her waiting period ends, or to confirm a pregnancy so he may keep her for its sake. Others say it is to prevent the reconciliation from being for the purpose of divorce, but rather with the intention of continuing the marital life.