Whether those who are subject to another's power are hindered from taking vows?

Objections

Objection 1 : It would seem that those who are subject to another's power are not hindered from taking vows. The lesser bond is surpassed by the greater. Now the obligation of one man subject to another is a lesser bond than a vow whereby one is under an obligation to God. Therefore those who are subject to another's power are not hindered from taking vows.
Objection 2 : Further, children are under their parents' power. Yet children may make religious profession even without the consent of their parents. Therefore one is not hindered from taking vows, through being subject to another's power.
Objection 3 : Further, to do is more than to promise. But religious who are under the power of their superiors can do certain things such as to say some psalms, or abstain from certain things. Much more therefore seemingly can they promise such things to God by means of vows.
Objection 4 : Further, whoever does what he cannot do lawfully sins. But subjects do not sin by taking vows, since nowhere do we find this forbidden. Therefore it would seem that they can lawfully take vows.