There's a chiasm in Exodus 19:20 that illustrates the relationship God wants with his people. He came down to us and called us. Now he wants us to respond by willingly coming to meet him.

.A - YHVH came down on Mt Sinai
...B - On the top of the mountain
.....C - YHWH called Moses
...B - To the top of the mountain
.A - Moses went up