Promises permeate human culture, and how well someone keeps them reveals their trustworthiness or lack thereof. This same standard applies to God, and His very divinity is at stake in whether He fulfills what He says. Critical scholars and atheists exploit apparent inconsistencies between the Old and New Testaments, claiming God changes character and fails to keep His word, using this as evidence that Scripture is merely human invention. This charge collapses, however, once one recognizes the crucial distinction between conditional and unconditional promises. Unconditional promises God fulfills regardless of the other party's actions, while conditional promises depend on the other party meeting specified stipulations. The Davidic covenant illustrates an unconditional promise. Through Nathan, God tells David that his throne and dynasty will be established forever, a promise reaffirmed in Jeremiah 33:17 and Psalm 89:34-37, where God declares He will not break His covenant or alter what has gone out of His lips, swearing by His own holiness that He will not lie to David. This promise has been traced through history and awaits final fulfillment in Jesus Christ. By contrast, Deuteronomy 28 presents conditional promises. God offers Israel extraordinary blessings of health, prosperity, safety, and national favor, but repeatedly attaches the word "if"—if they obey His voice and keep His commandments. Israel largely failed to uphold this condition, so God was not obligated to deliver the blessings. This was not a broken promise but an unmet condition; the contract required mutual performance, and Israel did not fulfill its part. The account of Abraham's near-sacrifice of Isaac demonstrates an unconditional promise being confirmed. Because Abraham had already proven, through obedience, that he feared God and withheld nothing, God needed no further proof and locked in the promised blessings. God swears "by Myself," a phrase clarified in Isaiah 45:22-23, where He explains that since He is God and there is no other, no higher authority exists by which He could swear—He stakes His own righteousness and unchanging character on the oath. Hebrews 6:13-20 draws out the significance of this oath, noting that God, wishing to show the heirs of promise the unchangeableness of His purpose, confirmed His word with an oath so that "it is impossible for God to lie." This gives believers strong consolation, an anchor of the soul, sure and steadfast, tied to Jesus Christ, who has entered the Presence of God as High Priest. The greatest promise sworn to Abraham, "in your seed all nations shall be blessed," anticipates Christ's sacrifice, resurrection, and priestly mediation, through which He provides everything needed for salvation. This distinction between conditional and unconditional promises ultimately assures believers that God is neither capricious nor unreliable. What He swears unconditionally, He accomplishes without fail, and what He withholds conditionally reflects human failure to meet His terms, not divine inconsistency. Because of this, believers can trust that God will complete the work He has begun in them, providing all things necessary to reach His Kingdom.