Obey God

Exodus 19:4-6---Ye have seen what I did unto the Egyptians, and how I bare you on eagles' wings, and brought you unto myself. 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.
Redeemed from the oppression of slavery; now what? Now obey, and you won't go back into slavery. As a people free from the things that enslave the world, they can be priests to the world. That was God's intention. He wasn't just building a little social club. Instead of becoming inwardly focused on themselves, they were placed on the trade routes of the world to be an example of what a nation led by God looked like. God was about to give them the Ten Commandments. First He asked if they wanted to accept the call. Then He instructed them, through the Law, how to be that example the world needed to see. If they could live that way, they would be priests to the world. In the days of Joshua and some of the reign of David, that was true of them. David's conquest of Israel's neighbors brought the influence of the Law to the surrounding nations. You have been redeemed from slavery too. It is not just to hang out in your church social group. It is to affect the world around you. Though you are not under the Law as your guide, you have a more intimate Instructor, the Holy Spirit. If you have dedicated yourself to being the LORD's vessel in every area of life, you will need His constant instruction to be the example the world needs. You become a priest to those your life comes in contact with, directing them to the Word of God and showing them an eternal perspective (1 Peter 2:5). You are an heir of this promise through the indwelling Holy Spirit.