Why is a vow made to other than Allah major shirk?

Question:
He says: Honorable Shaykh, may Allah grant you success, why did the scholars interpret the texts indicating that a vow made to other than Allah is major shirk, and why did they not interpret them as minor shirk, like an oath?

Answer:
Because a vow is an act of worship, and directing an act of worship to other than Allah is major shirk, just as if one supplicated to other than Allah, or slaughtered for other than Allah, or made a vow for other than Allah. So if one directs any part of worship to other than Allah, that is major shirk, or minor shirk. Yes.