I will sing of the steadfast love of the LORD, forever; with my mouth I will make known your faithfulness to all generations (Psalm 89:1) 

God’s faithfulness and never-stopping love is seen in the covenant God made with David (v3). God promised David that a descendent would come from his line and rule forever (v36). If you trace the line of David, the kings that follow after him are a “mixed-group.” Many of them turn away from God to follow after idols. They practice injustice towards God’s people and many do not follow God’s laws. Eventually, Jerusalem would be destroyed and the king removed from power. To the psalmist, all seemed lost. Yet, God was not finished with His people even though they rebelled against Him. He would bring his people back into their land, and send Jesus, the Son of David, to rescue His people.  

God’s faithfulness to David means that God keeps His promises. When God promised to never forsake you, He won’t no matter how you feel (Hebrews 13:5). When God promised to use everything in our lives to make us more like Jesus, He means it (Romans 8:28-29). When God promised to care for you, you can pray to Him knowing that He hears you (1 Peter 5:7). Because God is faithful, we can trust His word.