Paul culminates his warning against apostasy and encouragement toward love and faith with a beautiful, soaring exposition of assurance in Christ.
In Hebrews 6:17–20, God has guaranteed His promises for us in several ways. First, God has guaranteed His promise with an oath (Heb. 6:17). According to Scripture, God’s oaths to Abraham and David became the ultimate basis of confidence in God’s permanent favor for Israel. When Moses sought to secure God’s forgiveness for Israel after the apostasy with the golden calf, he referred to God’s oath to Abraham (see Exod. 32:11–14; Gen. 22:16–18). The implied strength of his plea was that God’s oath was irrevocable (Rom. 9:4; 11:28, 29).
Second, God has guaranteed His promises to us by the act of seating Jesus at His right hand. Jesus’ ascension has the purpose of corroborating the promise made to the believers because Jesus ascended as a “forerunner on our behalf” (Heb. 6:20, ESV). Thus, the ascension reveals to us the certainty of God’s salvation for us. God led Jesus to glory through the “suffering of death . . . for everyone,” so that He might bring “many children to glory” (Heb. 2:9, 10, NRSV). Jesus’ presence before the Father is the “anchor of the soul” (Heb. 6:19) that has been fastened to the throne of God. The honor of God’s rule has been waged on the fulfillment of His promise to us through Jesus.