When the Lord first called Jeremiah to be a prophet, He told him that his mission would be “to root out, and to pull down” (Jeremiah 1:10)—and in Jerusalem, there was plenty of wickedness to root out and pull down. But this was only part of Jeremiah’s mission—he was also called “to build, and to plant” (Jeremiah 1:10). What could be built or planted in the desolate ruins left by Israel’s rebellion? Similarly, when sin or adversity have left our lives in ruins, how can we rebuild and plant again? The answer lies in “the Branch of righteousness” (Jeremiah 33:15), the promised Messiah. The Messiah brings “a new covenant” (Jeremiah 31:31)—one that requires more than a superficial commitment or the outward appearance of devotion. His law must be “in [our] inward parts,” written “in [our] hearts.” That is what it really means for the Lord to “be [our] God” and for us to “be [His] people” (Jeremiah 31:33). It’s a lifelong process, and we will still make mistakes and have cause to mourn from time to time. But when we do, we have this promise from the Lord: “I will turn their mourning into joy” (Jeremiah 31:13).