No Word for Promise
In the Hebrew there is no special term for promise. Promise is simply "word." God's word is His promise. With God no more is needed. He is so powerful and so unchangeable that a word is enough. He speaks, and it is done. Those who marched around Jericho dared, on the authority of God's Word alone, to claim a promised victory when there were no signs of this victory being accomplished.
God often spoke to the prophets as if His promises were already fulfilled. In Joshua 6:2, God spoke in the past tense as though the Israelites had already fought and won the battle: "See! I have given Jericho into your hand."
When God gives words of comfort or assurance those words will endure forever; it's not just for that moment. That word is good from that point on. "Your word, O Lord, is eternal." Ellen said when praying for some direction for her life as a college student, the Lord gave her Ruth 3:11: "And now, my daughter, don't be afraid. I will do for you all you ask." That promise not only gave her confidence that God would guide her then, but has remained a resting place for her in the years since.
Mary said that when she was a young mother, the Lord gave her Moses' words in Deuteronomy 1:17: "Bring me any case too hard for you." When her children's problems were too big for her, she took them to Him. Again and again, she believed that Word to be her assurance that God would give her the answer she needed.
Thank You, Father, for Your precious words that are fulfilled when I believe them.
"For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished" (Matt. 5:18).