Jeremiah 33:3
Call to Me, and I will answer you, and show you great and mighty things, which you do not know.’

What a great comfort to Jeremiah while in prison, to hear from God in this way.
However, it is not just a promise to Jeremiah. It is one to you too.
I believe God desires to show us great and might things. What is more great and wonderful than God Himself.
Call on Him and He will let you experience Him in the fullest.
Why should you trust God?
He said it Himself in the previous verse – Thus says the Lord who made it, the Lord who formed it to establish it (the Lord is His name) Jeremiah 33:2
The Lord God establishes it.
It cannot change or alter.