How do we know that God controls salvation?

The psalmist clearly articulates the belief that salvation is entirely by God's initiative and action, as seen in the declaration, 'salvation is of the Lord.' The understanding from this text is that God operates through His sovereign will, and it is not a collaborative effort with humanity. This entry into salvation is affirmed throughout Reformed doctrine, which underscores that it is God who elects, calls, and redeems His people, entirely by His grace and not based on our deeds. The psalm serves as a reminder that God has shown His faithfulness in the past, leading to the assurance that His control over our salvation is constant.