Help identifying part of a classical piece (maybe Mozart?)

[FalsePerceptions]

Hello, I feel sure that someone out there can help with this in a matter of minutes, and save me a few hours.
I'm trying to identify a theme from (I think) one of the middle movements of a piece of classical music. I think it's Mozart (a symphony, I reckon), and pretty sure the melody is played by the clarinet.
Don't know what key it's actually in, so I'm giving notation in C major here as it's easiest.
It's three beats to a bar. Capital letters are minims, lower case are crotchets and italics are quavers. In each phrase, the second note is the g below the first note, then it jumps up so that most of the following notes are above the first note. If that makes sense....

Any ideas, anyone?? I can offer a great deal of gratitude as your prize.

C g e d c b d f e d c b (rest rest)
D g f e d c e g e f d c (rest rest)

Thank you!!!

This has brought back memories of my family sitting around humming hymn tunes trying to recall my mum's favourite for her funeral. We remembered, it was How great thou art. I remember how it felt when we could say, Yes! That's the one! It just made everything feel a little bit better, thinking that she'd approve.
Sending a hug, OP.

This post has literally brought tears to my eyes this morning. What a fantastic example of people helping others with SUCH a niche request, and for op to be able to play this at her mum's funeral. Hurrah mumsnet!

Sorry for your loss op x

I've caught up with the thread and it's lovely to see how this situation resonates with other people.

Also I'm glad it's demonstrated the power of the communal mind for this kind of thing. Whatever it is you want to know, there will always be someone who knows (or who knows how to find out).

This has been a lovely warm thread, and everyone on it has been so kind. Thank you all.