Will we need to breathe in heaven?
Although I’m guessing the answer’s no because of the resurrection bodies and all. Although didn’t Jesus eat fish and bread?
In 1 Cor 15 44 the Bible calls our new bodies “spiritual”. But this does not mean our new bodies won’t be physical. As you correctly point out in your question, Jesus’ “spiritual” body was still physical, and his body was the model for our new bodies. (1 Cor 15 48, 49)
The same passage tells us our bodies will be glorious, powerful, imperishable and immortal. (1 Cor 15 42-43, 53)
If our bodies are immortal, it follows that breathing (as we do it now) will not be essential to life.
So if we DO breathe with our resurrection bodies, what do we do it for?
Well one of the things you do with your breath is to force it through your vocal cords to make a noise.
And you’ll be glad to hear that this function of breath still continues with your new bodies. In Rev 15 3 all God’s people are heard singing. You’re there yourself. No, over THERE, just right of the middle, can’t you see yourself? You’re the one that looks like you!
What else can you use your breath for? Well look what Jesus does with his! In 2 Thess 2 8 Jesus defeats the antichrist “with the breath of his mouth”. I wonder if OUR breath will be a weapon like his?
Of course, as far as God is concerned, “Breath” is the way He confers life on us. In the Valley of Dry Bones story in Ezek 37, God commands Ezekiel to call on the Winds to breathe life into the lifeless bodies.
And, of course, God breathed life into Adam.
In this context, an interesting fact is that the Hebrew for “wind”, “breath”, and “spirit” is the same word “Ruach” (Pron. Roo-ak).
And in case you thought that was an accident, the Greeks did the same thing with the same words – all three were one word in Greek, “Pneuma”, (which is where we get our word “pneumatic” from.)
So, I think that not only will we have breath in our new bodies, but also the breath will be God’s own breath (ruach) coming from His Spirit (Ruach), which he will use to give us that imperishable life in our spirit (ruach).