The last verse of Psalm 96 begins with the word “for.” That is not unusual, for other psalms follow that same pattern and the word is found about 9,000 times in the entire Bible. The word “for” often introduces a cause, the effects of which have already been enumerated. (Example: “For” in Galatians 3:27 is the cause [baptized] of the effect in verse 26 [being sons of God].)
Look at Psalm 96. The last verse reveals, “For He is 
coming, for He is coming to judge the earth.” The judgment of God is certain, and in this verse, it is set forth as a cause for action. What actions are called for in Psalm 96, as a result of (or effect of) impending judgment?
“Sing to the Lord…Sing to the Lord…Bless His name…Proclaim the good news of His salvation …Declare His glory among the nations…Give to the Lord…Give to the Lord the glory due His name…Bring an offering…Come into His courts…Worship the Lord…Tremble before Him… Rejoice…Be glad…Be joyful.” When you think of the judgment, is this your reaction?