We get a couple of very important terms about gospel ministry from the prophet Isaiah. One comes from Isaiah chapter 43 in this phrase: "You shall be my witnesses." It's a phrase that we hear in Acts chapter 1 verse 8 when Jesus is sending out his witnesses in the power of the Holy Spirit. The question is, witnesses to what? And the context of Isaiah 43 tells us, and that is, a witness to the nations that I am the only God, the only one who saves, the only king, that the only true kingdom, the only true Lord is the God of Israel — Yahweh, the God who saves, the God who redeems his people and the God who reigns, the Lord who reigns. So, we have that one term from Isaiah 43 that is very important for evangelism in Acts 1:8. Another important term is the term "gospel" itself in Isaiah 52: "How beautiful are the feet of those who bring good news." Well, good news of what? Again, the importance here is the idea of God's kingdom, that God as the king of his people has protected them in battle, has rescued them, has delivered them in battle, and that his kingdom is going to be the one that endures forever. And so, what we get in this sense of Isaiah 52 is that the gospel is connected to God's kingship in that bringing the announcement of good news, yes, it's about forgiveness, yes, it's about a return to a covenant relationship with God, but what that really means is that God's reign would be effective in our lives, in the places where we live, in every aspect of life, because if our king wins the victory in battle, then it's going to be his law that takes root in that place, in that kingdom, in that realm. And so, two very important terms that inform our evangelism, inform our understanding of gospel ministry — the term "witness" and the term "gospel" — from Isaiah.