The writer of Hebrews tells us that God confirmed the promise made to Abraham by an oath, to show the immutability of his counsel unto the heirs of promise (Hebrews 6:17). God's oath was made "that we might have a strong consolation by two immutable things" (Hebrews 6:18). Those two things are described as the two things in which it was impossible for God to lie. Notice the it, which serves as an expletive to tell us the subject follows the verb. The subject is the infinitive to lie. To lie was impossible for God, especially in these two things. These two immutable things are a reference to the two covenants, two declarations of God's oath: the Old Testament and the New Testament.
The Old Testament and the New Testament agree on the way of salvation. Early in his Roman epistle, the Apostle Paul declares that the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe is witnessed to us by the law of Moses and the prophets (Romans 3:21-22). At the close of the Roman epistle, Paul declares that the revelation of the mystery, which was kept secret since the world began but is now made manifest (a reference to the New Testament) was made manifest according to the commandment of the everlasting God, made known to all nations for the obedience of faith (a reference to the Old Testament). These two are not only in one accord, they are in agreement with Paul's gospel and the preaching and teaching of our Lord Jesus Christ (Romans 16:25-26)
Who can lay claim to God's strong consolation? All who have fled to Him for refuge, to lay hold upon the hope that is set before us (Hebrews 6:18). This hope is the anchor of our soul, both sure and stedfast. This hope is the forerunner of our faith, even Jesus, who has entered into that holy of holies for us. He has been made high priest forever, after the order of Melchisedec (Hebrews 6:19-20). Have you fled to Christ? Have you anchored your soul?