Is it permissible to perform the two rak'ahs of gratitude that you vowed to pray daily?

Whoever swears an oath to perform a recommended act of obedience, it is disliked for him to break it, and he owes expiation. Upholding this oath is an act of obedience to Allah Almighty. If he does not perform it, he has broken his oath and must expiate. As for the ruling on swearing an oath to perform an act of obedience, there are two views among scholars: The first is that it is recommended, and the second: it is not recommended, because it was not the practice of the Prophet, peace and blessings be upon him, and his companions.