Hi, I am working on some devotional prayers to St. Brighid. I need translation help from anyone who is willing. These are for putting butter into the fire while being said.

Unto the sun I am offering this gift. This is not mine, this is Thine.

Unto the fire I am offering all. This gift is not mine it is Thine.

Thanks in advance! Go raibh maith agat!

For the first prayer, I'd like to replace sun with Brighid.

Here's a start.

Don ghrian a ofrálaim uile. Ní liomsa é, is leatsa é.

Don tine a ofrálaim uile. No liomsa é, is leatsa é.

My translation isn't as elegant as the English (it doesn't rhyme z for example), but it's a start at least.

Wait for correction and/or confirmation.

Looks good with minor changes.

Do Bhríd a ofrálaim an bronntanas seo. Ní liomsa é, is leatsa é.

Don tine a ofrálaim uile. Ní hé an bronntanas seo liomsa é, is leatsa é.

Wait for more input.

Looks like I mixed up a few things with the quote, and forgot "Bríd". For the second line, wouldn't "ní liomsa an bronntanas seo,..." Be a bit simpler?

I didn't even see all that right away. It took me a few times to get it all right.

As far as ". . . ní liomsa an bronntanas seo . . ." that's your call. Using "é" may not even be right.

Yes.
Ní liomsa an bronntanas seo
or:
An bronntanas seo, ní liomsa é.

I'd think Ní hé an bronntanas seo liomsa é means something different ("It isn't this gift with me") resp. it is wrong.
Liomsa has to be the only predicate to mean " smth. is mine".

You are right.