God's word is truth
Now when people take an oath, they call on someone greater than themselves to hold them to it. And without any question that oath is binding. God also bound himself with an oath, so that those who received the promise could be perfectly sure that he would never change his mind. So God has given both his promise and his oath. These two things are unchangeable because it is impossible for God to lie. Therefore, we who have fled to him for refuge can have great confidence as we hold to the hope that lies before us. Hebrews 6:16-18 NLT
God gave Abraham a promise that was confirmed by an oath. When a witness is called upon to testify in the court, he or she will be asked to make an oath by saying “so help me God.” This is done so that the testimony will be truthful. This is how we settle issues, “call on someone greater than themselves.” In the same way, God made an oath “so that those who received the promise could be perfectly sure that he would never change his mind.” It should be noted that a mere statement of God’s intentions was sufficient enough to provide a foundation for our trust. Yet, God provided an oath so that we will not doubt what He promised. This is why our salvation is assured not only because God promised but also, He made an oath. “These two things,” His promise and oath, “are unchangeable because it is impossible for God to lie” (Hebrews 6:18). He does not have to make an oath, yet God did so He can accommodate our human frailties and our doubts. So, God’s promise to Abraham and to us, His heirs, will come true. “…your word, which is truth” (John 17:17). Not only that God’s word is truth but also, God does not lie. “This truth gives them confidence that they have eternal life, which God—who does not lie” (Titus 1:2). God’s essence is the truth and His Word is truth. There is no way that God’s promise will not come into fruition for His word is doubly sealed by His promise and His oath. This is why, the hope that we took hold of when we surrendered our life to Him is sure. Our hope is not based on optimism or sentimentalism for our hope does not come from within but from God through Jesus Christ our Lord. The Lord Jesus Christ is the substance and the foundation of our hope.