Psalm 145 is one of the few songs of David that is lacking his usual pleas with God to destroy his enemies. In this song he rises above his anger or fear or depression to just give absolute praise to Yahweh.
"I will extol you, my God and king, and bless your name forever and ever. Every day I will bless you and praise your name forever and ever. Great is the Lord and greatly to be praised, and his greatness is unsearchable." Psalm 145:1-3 ESV
If someone asked you to "tell me about your God", how would you answer that request? I seriously doubt that quoting a lot of scripture would be what most people would be wanting to know from you. Having had this experience more than a few times in my years of service in His kingdom, I have done a less than adequate job of testifying about my Father to someone who didn't know Him. I guess my instinct as a minister and teacher has generally been to assume that reading scripture with them is what they wanted to know. Without question, we do have to get to the word of God at some point because that's how we lead others to Jesus and His kingdom. However I have learned that generally they just want to know if I KNOW God and what that means for my life.
I think most people who ask that question of Christians aren't looking for us to try to "prove" something to them but just to convince them that we truly know who our Father is and what that might mean for them. David's understanding is that "his greatness is unsearchable". To me that means God isn't some idea or hypothesis that can be proven by scientific testing in a lab. We can only know Him by seeking to make an honest connection within our own spirits. There are multitudes of folks who can quote a lot of scripture but don't really KNOW God or His Son. There are many who attend some kind of religious worship gathering regularly whose lifestyle betrays their professed beliefs.
So, tell me about your God may not mean "quote me some Bible scriptures", but "how do you feel about your God?"
We will pursue this thought further as we go through Psalm 145.