Psalm 122 is about going to the house of the Lord. Verse 4 says "Where the tribes go up, the tribes of the Lord, to the Testimony of Israel, to give thanks to the name of the Lord." (NKJV)
To the Testimony of Israel.
This is one of those obscure phrases that translators disagree about, but in the New King James, it's capitalized. That makes me think it's God.
Imagine that moment in the courtroom. "Does the accused have anything to say for herself?" I don't have to say a word.
God is my Testimony.
I don't have to answer for my sins.
God is my Testimony.
That's the reason to worship and give thanks to the name of the Lord.