Like a script writer who first writes and completes the script, and then gives it to actors to play out the script, God sees the end from the beginning and completes it before He takes us on the journey. So, when God is saying, I know how this ends, it is going to work out for your good, don't fret. Fretting is as ridiculous as an actor fretting that he is going to die in a scene, and the script writer is there saying, no you aren't going to die. I know how this ends, I wrote out the entire drama and I know you don't die in the end. So don't be ridiculous; don't fret. God knows how this all ends. You can rely on His promises.