Psalm 136 is very interesting when you do a word study! Look at verse 1:
1 O give thanks unto the Lord; for he is good: for his mercy endures for ever. KJV
Do you know that "he is" and "endures" are not actually in there at all? The translators thought that it would make things clearer if they wrote it that way. This is what it ACTUALLY says:
1 O give thanks to Jehovah, for good, for His mercy forever.
Even Young's Literal Tranlsation adds a word in brackets to try to make things clearer:
1 Give ye thanks to Jehovah, For good, for to the age [is] His kindness. YLT
I LOVE this Psalm, just the way we have always known it! I do believe that He is ONLY Good AND that His mercy and loving-kindness are forever. BUT, if we look at it literally, the command is so much more about OUR response to His goodness! What I believe this verse is meant to say to us is this:
"Give thanks to the LORD (Jehovah - the Covenant Name of God), FOR His Goodness and FOR His wonderful mercy FOREVER!"
There should never be a moment when we stop being thankful and giving thanks for WHO He is and for all that He has done! Recognizing that should give us complete encouragement that the God Who has done so much for us already will not stop NOW! I love the new song by Hillsong United called "Oceans" where there is a line that says "You've never failed me and You won't start now"! No, I am NOT trying to rewrite Scripture! I AM trying to enhance our understanding of it so that we can continue to walk in the fullness of all that the Word of God contains and promises! AMEN! Let's listen again to "Oceans" again. It is POWERFUL!
Shalom in Him!