This is the incident of Moses at the Burning Bush. God decrees at the outset that Moses and his people would serve God on this mountain, which was Mt. Horeb, also known as Sinai. That would be the culmination of the 7 weeks.
But those 7 weeks were a perfect span of time that portended something momentous and, all things considered, incredibly merciful: A covenant with their Creator and Deliverer. And true to His word, Moses and the people worshipped God on the same mountain on which He originally met with Moses.