Most of the time, we think this refers to just speaking in tongues. Yes, it’s part of speaking in tongues, but this refers to how loving, kind, unique, and powerful the Holy Spirit is. The Bible says the best of us get to a place where we cannot pray the way God wants us to. The weakness there refers to many things: weariness, tiredness, overwork, underwork, etc. But in this case, there’s a way that, as you grow with God and do more for Him, God expects more from you. Sometimes, God expects more from you because He just gave you more.
And the funny thing is, when God adds more to you, the Bible tells us that He does exceedingly, abundantly, above all that we can ever ask or imagine. So, you’re busy thinking, ‘I’m asking God for this, I’m imagining this, I’m expecting this,’ and God says, ‘I’m going beyond what you ask or think.’
When we have finished asking God for big things, the reality of circumstances sets in. Instead of expecting what we asked for, we bring down our expectations, especially if expectations have been met with inevitable disappointments. Now, when you bring down your expectations, God shows up. And instead of God working with you according to your expectation level, which, of course, you are happy enough to have certain expectations met, the Holy Spirit shows up and goes to that realm where you were when your faith was high.