What is the ruling on one who says, "I have vowed myself to this religion," while not intending thereby a vow, but rather to urge himself to action?

The statement: "I have dedicated myself to this religion" is not considered a legal vow (nadhr shar'i) that necessitates fulfillment, especially if the speaker did not intend it as a vow but rather as a motivation for self-exertion in work. A legal vow is when a responsible, competent individual obligates themselves to Allah through their statement "Lillahi 'alayya" (It is binding upon me for the sake of Allah) or "Nadhartu Lillahi" (I have vowed to Allah). Scholars have differed regarding vows of acts of worship that do not have an origin in obligatory duties. The Hanafis believe such vows are invalid, while the Malikis, Shafi'is, and Hanbalis consider them valid and binding. If one says: "It is binding upon me for the sake of Allah to vow that I will serve this religion," then their vow is fulfilled by working for it and inviting others to it in any possible way.