“Brethren, I do not count myself to have apprehended; but one thing I do, forgetting those things which are behind and reaching forward to those things which are ahead,”Philippians 3:13 NKJV
It's not healthy to hold onto the past, especially memories that are painful and sad. It will hinder you, it may even stop you completely from moving forward. For an example - If a person prepares to go out into the rain, puts on their coat, galoshes, walks outside, and closes the door, but doesn't let go of the door handle; they're stuck. Imagine what that looks like! A person with their coat on, holding onto their front door knob not letting go! They're not going anywhere. Even though you may know God's promises for your life, you're not going anywhere if you don't let go of your past pains. We have to let go so we can run to where we need to go. Let go of the handle and move forward.