When it comes to the matter of praising and thanking God in the Bible, many of the motivations we are given are similar. We saw recently that we should praise God because He is good, and here we are urged to thank Him for the same reason. One general guideline that might be applied is this; we should praise Him for Who He is and thank Him for what He does. The overlap comes, of course, because the wonderful things that God does arise from the wonderful Being that He is!
The Psalmist gives us another reason to thank God here, and it is a refrain that is taken up many times over in different parts of the Bible. We should thank God because His lovingkindess is everlasting. This word is variously translated as kindness, loyalty, mercy, loyal deeds etc. It indicates a faithful love and benign disposition on the part of God towards the recipients.
At this point it would be good to pause and consider what our sins have merited from God, and then to consider that the retribution we richly deserved has been taken away and replaced instead by this lovingkindness, this faithful love. What a transformation in our situation! Then we need to look back at our text and see that this is no temporary phenomenon. No, God settles this lovingkindness upon His chosen ones everlastingly!
Finally, let's pause and remember that it is the finished work of Christ alone that brings about this change in our standing before God. It was His willingness to be born in human likeness, born under the law (as we are), His living a perfect life in our place and His death on the cross as our Substitute that has deflected God's wrath from us and earned for us His everlasting lovingkindness!
God has done all this for us, but then we can reflect on the way we all partake of His mercy every day that we live - His mercies are new every morning! All in all, we are left with a compelling reason to pray - to thank our glorious Father in heaven for the mercy He has shown us in Christ!