As Peter quotes Joel, the Old Testament prophet, it’s vital to see that he prophesies about two different ages. “In the last days” God will pour out his Spirit and secondly there is still to come v31 “the great and dreadful day of the LORD.” The coming of the Spirit is a sign that they are in the last days before God comes to judge the world at the end of time. They live between Jesus first coming; God incarnate come as a baby in Bethlehem to live, die, rise again, ascend and the pour out the Spirit and his return not as a baby but as the judge of all the earth.
This deluge of the Holy Spirit, these languages are a sign that they live in the last days. That the Messiah has come. Why does it matter? Because these last days are the days of opportunity, when “everyone who calls on the name of the lord will be saved.” The time between Jesus pouring out the Spirit and his return as judge are days of opportunity, days of salvation, so call on him.
The coming of the Spirit helps us see when we live too, because we also live in the last days. Christ has come, he’s poured out his Spirit, salvation is available and it’s urgent. Just as there was a historical Day of Pentecost there will be a day when Jesus returns. A day when God who sees everything, who reads not just our actions but our hearts, our motives and our hidden thoughts will call us to stand before him. God will come and he isn’t looking for some vague shifting notion of ‘niceness’ or being ‘good’, but for a wholehearted devotion to him and a love for our neighbours as we love ourselves. That day is as certain as the day of Pentecost. We need to understand that this is when we live, between the days.
Why? Because it makes it urgent that we respond. There will be a day when Jesus comes back and we stand before him as our judge and everything about us will be laid bare. We’ll be like an open book to him, there’ll be nothing hidden. Imagine for a minute that I had on a memory stick everything you’ve ever done, every word you’ve ever spoken, everything you’ve ever thought, every reaction you’ve ever had. It would be embarrassing to put that up on the internet wouldn’t it. We’d be exposed. People would see what we were really like. God already knows and one day we will stand before him and nothing will be hidden.
But now before that day we have the chance to be saved, to be rescued from facing God’s white hot anger against our sin, the symptoms of which we see in our actions. Why does it matter that we understand when we live because salvation is available now.
And secondly, because it injects urgency into our witness for Jesus. We live and witness knowing that Jesus is coming back. We need to let that reality fuel our prayers for our friends and family, compel us to engage with our community as a church, and propel us outwards to witness to who Jesus is.