Is the phrase "I have obligated myself" among the explicit wordings of a vow (nadhr) that do not require an intention, or among the allusive wordings that do require an intention for their meaning to take effect?

The phrase "I have obligated myself to such and such" from among the acts of obedience is considered an explicit vow (nadhr), due to its clear indication of commitment. It is similar to saying "Upon me is such and such," and jurists have considered it among the explicit wordings for a vow, just like the saying "For Allah is upon me such and such."