"I will sing of the Lord's great love forever; with my mouth I will make your faithfulness known through ALL generations.
I will declare that your love stands firm forever, that you established your faithfulness in heaven itself."
The theme of Psalm 89 is God's promise to preserve David's descendants. God's promise IS fulfilled in Jesus Christ, who will reign for eternity. The love and kindness promised to David is ours IN Christ.
These verses are as complicated or as simple as we make them. I choose to take the simple side and literally think about the happiness and joy we bring to others by our singing. Don't you just love to sing with children? They naturally have such joy in their hearts. Why not find some new or old children's songs that praise God and teach them to your children or grandchildren.
What a great way to teach the next generation about what a Mighty, Awesome, Loving God we serve!