Verses 6-8 mentions Moses, Aaron, and Samuel as priests who called upon the LORD on behalf of the rebellious people. These weren’t perfect men, but they strove to keep God’s ordinances. And God responded to their pleas. The LORD is always attentive to the cries of the people (even when we don’t think He’s listening). God can’t tolerate defiance. He is holy, and He expects His people to emulate Him in being set apart from the world and its ways. Yet, as much as He takes sin seriously, He takes forgiveness seriously. This is God’s lovingkindness displayed, His mercy (compassion) and grace (undeserved favor) bestowed on any who confess their sins. His attentiveness and willingness to forgive even the most heinous of sins when we repent is another reason to exalt Him. The mention of His “holy hill” here refers Mount Zion outside of Jerusalem. Again, why do we exalt Him? Because He is a holy, righteous, just God who reigns over all the world. When we truly see God for who He is, we are changed, and we willingly add our voices in declaring, as the Psalmist did at the very beginning of chapter 99, “The LORD reigneth!”