Generosity and trust

Had a good think last night about training Remy. What I realise is that I'm forgetting the very very basics (not good english, I know). Thinking first of all, above all else the mobilisation of the jaw, which I honestly believe is the key to the whole body. I've been thinking we're doing ok and I suppose we are, but he's only partly giving his mouth, only partly trusting my hand and even though it's so bloody obvious I've been missing it in my quest to progress.
Remy bends easily to the left, in fact he wants to be flexed left and I know horses have a weak/ strong - soft / hard side but if I offer him a treat from the saddle (or from the ground for that matter) he can stretch both sides easily, so I believe it's a refusal/reluctance on his part, for whatever reason, it's a contraction of his muscles rather than a real underlying lack of suppleness.
Today we started from the ground and started at the beginning, asking for the release from a lift of the bit to the corners of the mouth. He was hesitating, not releasing immediately and when he did release, he didn't retain it, but after a few attempts he started to respond and relax. I then moved to the left side, outside rein over the top of the neck and asking for the release and then a release into a left flexion, keeping the relaxation and allowing him to extend his neck, again keeping the release and relaxation and mobility of the jaw.
Moving to his right side, feeling the reluctance through the rein, but then the release and relaxation, acceptance, nice right flexion and then allowing the extension of his neck, still willing to give his mouth.
I wanted to sit-on but was loathe to muddy the waters, but I really wanted to sit on to see if the work could continue from the saddle.
So on I got and as I picked up the reins to begin he responded and I felt immediately the release and acceptance as he mobilised his jaw, with a beautiful soft, anything is possible feeling  in my hands. This is what was missing, the real gift of generosity and trust.
A calm stillness, self balance and self control, we walked a circle on each rein, just one circle, not wanting to be too greedy, retaining that beautiful feeling in my hand and softness through his body. It was a moment of pure joy. I got off with the realisation that I'm a very very lucky girl!!!