As Jeremiah writes, He is coming again to establish justice and righteousness.
As Jesus says, He is coming again in terrifying fashion to judge. He urges His disciples, and us, to be ready for that day, so that we can stand ready to receive Him, living righteously and not so focused on the cares of the world. We do so by living in love toward one another, in good conduct shown to us by Christ, making Him present now.