There's a lot that could be said about this verse, but to me the thing that rings true is that even when he didn't feel worthy of it, God chose Jeremiah. This is a great opportunity, but also extremely scary. In a way, God is counting on Jeremiah to preach and share a difficult message with God's people.

In the same way, each of us as disciples has been commissioned by Jesus to bear fruit (John 15:16). That's an incredible responsibility, and one that oftentimes seems really overwhelming to me, just like it surely did to Jeremiah. Yet God has chosen me to share his message, just like Jeremiah. I can either cower away from that (much like the wicked servant in Matthew 25), or I can own up to it and believe that God is right there with me, leading and working the whole way.

Jeremiah 1:5