What is the ruling on a vow made by someone who abandons prayer due to negligence and laziness, including the views of the jurisprudential schools of thought, especially the Hanbali school?

A vow made by someone who abandons prayer out of negligence and laziness is valid and must be fulfilled, unless their abandonment of prayer was due to a denial of its obligation, because they do not exit the fold of Islam according to the majority of scholars. The Hanbalis hold that such a person is a major disbeliever, yet they consider their vow valid and obligatory to fulfill once they embrace Islam, based on the hadith of Umar ibn al-Khattab regarding his i'tikaf (seclusion) during the pre-Islamic era.