Israel packed up and moved to the foot of Mt. Sinai; it was now the third month. God called to Moses, and he went to God on the mountain, and God made them a covenant offer:
"Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine: And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel." Exodus 19:5-6
They agreed to the covenant. This is the same as accepting Jesus as our Savior; we must agree to be blessed. God approached them, not the other way around. He must call you out of the multitude of people on earth, offer to be your God, you accept it and then obey his voice. God's Holy Spirit is the one who called to us while we were still in our sin.
God gave Israel three days' notice that they must clean up before coming to him, leave their worldly cares behind, and be ready to receive him on the third day, which happen to be 50 days after leaving Egypt: Pentecost. God came down, and everyone saw the thundering cloud full of lightning and heard an extremely loud trumpet; I'm sure they were overwhelmed with excitement and fear.
The point is that God comes to us and makes us a covenant offer. If we accept it, we must then obey his voice. God offered himself to Israel, and Jesus has offered himself to us. It's up to us to accept his offer and obey his voice. When you accepted Jesus, you entered into a covenant with him, and that's a big deal! You have the Holy Spirit; listen to him and allow him to be your guide.