Why is knowledge of God's Word important for assurance?

The sermon highlights that true assurance cannot be based on subjective feelings or personal works but must come from the objective truth found in the Scriptures. The written Word of God provides clear revelation about God's nature, His promises, and the means by which we can understand salvation. In Psalm 119:105, it states that God's word is a lamp unto our feet and a light unto our path, guiding believers towards true understanding and assurance. This foundation allows believers to grasp the reality of their salvation and God's faithfulness throughout history.