God's Will done how?

Last night I was saying one of my usual prayers, "May God's Will Be Done", which I admit has never made sense to me. We have free will, so it seems that if we don't choose something, God cannot make it happen. Then I had a reversal: I saw someone else saying the prayer, and I saw myself being available, and willing to do something that God would wish for us. Ah! Now it all makes sense! "May (someone out there choose that) God's Will be done (through them)." Got it!