Why did the fatwa differ between considering the phrase "If I get a job, I will donate my first salary" as a vow, and considering similar phrases like "I will do such-and-such, or I will donate such-and-such, if such-and-such happens" as not explicit vows unless accompanied by intention? And is saying "Mmmmmm" in agreement with a sister's statement, "When Allah gives you a job, you will spend your entire salary on this child," considered a binding vow, or a promise that must be fulfilled, given that there was no intention of vowing at the time?