John Gill Commentary Judges 11:31

"then it shall be, that whatsoever cometh forth from the doors of my house to meet me, when I return in peace from the children of Ammon, it shall be Jehovah`s, and I will offer it up for a burnt-offering." — Judges 11:31 (ASV)

Then it shall be, that whatsoever comes forth of the doors of
my house to meet me
If this phrase, "to meet me", is meant intentionally, then no other than a human creature can be meant; a child, or servant, or any other of mankind; for none else could come forth with a design to meet him: but if this is to be understood eventually, of what might meet him, though not with design, then any other creature may be intended; and it must mean what came forth first, as the Vulgate Latin version expresses it, or otherwise many might come forth at such a time:

when I return in peace from the children of Ammon :
safe in his own person, and having conquered the Ammonites, and restored peace to Israel:

shall surely be the Lord's ;
be devoted to him, and made use of, or the price of it, with which it is redeemed, in his service: and I will offer it for a burnt offering; that is, if it is what according to the law may be offered up, as an ox, sheep, ram, or lamb; some read the words disjunctively, "or I will offer it". It shall either be devoted to the Lord in the manner that persons or things, according to the law, are directed to be; or it shall be offered up for a burnt offering, if fit and proper for the service; so Joseph and David Kimchi, Ben Melech, and Abarbinel, with others, interpret it; but such a disjunction is objected to as improper and ridiculous, to distinguish two sentences, when the one is more general, and the other more special.