Understanding Hebrews 6:17-18 in Depth: God’s Oath, Our Hope

God’s Unbreakable Promise in a Time of Testing

The original readers of Hebrews were Jewish believers under pressure, tempted to abandon their faith in Jesus and return to the safety of familiar religious routines.

They were facing real suffering and uncertainty, and the author writes to remind them that Jesus fulfills and surpasses everything the old covenant offered. God’s promise to bless His people, first given to Abraham, was confirmed by His word and by a solemn oath, which makes it doubly secure. As Hebrews 6:17-18 says, 'So when God desired to show more convincingly to the heirs of the promise the unchangeable character of his purpose, he guaranteed it with an oath, so that by two unchangeable things, in which it is impossible for God to lie, we who have fled for refuge might have strong encouragement to hold fast to the hope set before us.'

This hope isn’t wishful thinking - it’s a firm anchor for the soul, rooted in God’s unchanging character and His oath, pointing us to Jesus, the forerunner who entered the holy place on our behalf.

Two Unchangeable Things: Why God Swore an Oath

God’s promise and His oath together form a firm foundation for our faith, not because He needs to prove Himself, but because we need assurance.

The author of Hebrews draws from the legal principle in Deuteronomy 19:15, which says, 'A matter must be established by the testimony of two or three witnesses.' According to this standard, God confirms His promise with two unchangeable guarantees - His word and His oath - so we can be certain. Since there is no one greater for God to swear by, He swore by Himself, as it says in Hebrews 6:13-14: 'For when God made a promise to Abraham, since he had no one greater to swear by, he swore by himself, saying, “I will surely bless you and multiply you.”' This was not to strengthen His word, which is already true, but to strengthen our weak hearts. In doing so, God meets us where we are - offering more than facts, offering a promise we can cling to.

In the ancient world, oaths were sacred and binding, often calling down judgment on oneself if the promise was broken. When God takes an oath, He is not admitting uncertainty. He stoops to our level, using a human custom to demonstrate His seriousness. The phrase 'it is impossible for God to lie' means more than that He tells the truth; it declares that His very nature is truth. He cannot act against who He is. So when He swears by Himself, He is saying, 'Let My own character be the guarantee.'

It is impossible for God to lie.

This changes how we see trials and delays. If God’s purpose were based on shifting feelings or changing plans, we could lose hope. But Hebrews shows us it’s not. His promise to Abraham was fulfilled in Christ, and we, like Abraham, are heirs of that same promise. We hold fast not because we are strong, but because the hope set before us is anchored in something unshakable - God’s unchanging character and His oath. This is the hope that sustains us when everything else feels uncertain.

Fleeing to God for Refuge and Holding Fast to Hope

The image of fleeing for refuge parallels the ancient Israelite cities of refuge, safe places for the endangered, and it mirrors how we turn to God for safety from sin and fear.

In Numbers 35:11, God instructed Israel to set aside cities where someone who accidentally caused death could flee and find protection until the high priest died. This was not a legal loophole; it illustrated mercy. In Hebrews 6:18, the writer uses this idea to show that we, too, are fleeing - spiritually - toward God, not from a physical enemy, but from the weight of guilt and the fear of judgment.

We who have fled for refuge might have strong encouragement to hold fast to the hope set before us.

Our hope is not a vague wish. It is an anchor, as Hebrews 6:19 describes: 'a hope set before us as an anchor of the soul.' That hope is Jesus, who entered heaven itself on our behalf. Because of His work, we can hold fast, not by our strength, but because God’s promise and oath make our refuge secure.

The Oath That Anchors All History: From Abraham to Christ’s Eternal Priesthood

The oath God made to Abraham was not the end of the story, but a divine promise set in motion toward its fulfillment in Jesus, our eternal high priest after the order of Melchizedek.

In Genesis 22:16-17, God said to Abraham, 'I have sworn by myself, declares the Lord, because you have done this and have not withheld your son, your only son, I will surely bless you and make your offspring as numerous as the stars of heaven.' This oath was not about descendants alone; it pointed to a single Offspring, Christ, through whom all nations would be blessed. Later, Psalm 110:4 declares, 'The Lord has sworn and will not change his mind: You are a priest forever after the order of Melchizedek.' Hebrews 7:21 quotes this to show that Jesus’ priesthood is not temporary or transferable like the old priests. It is permanent and guaranteed by God’s oath.

Jesus’ priesthood is secure because of more than His sacrifice; the oath that appointed Him also guarantees it. Unlike the Levitical priests who came and went, Jesus holds His priesthood permanently, not by lineage but by God’s sworn promise. This means our access to God isn’t based on rituals or human effort, but on an unchangeable oath from God Himself. When life feels unstable - when guilt whispers or fear shouts - we can remember that Jesus stands before God for us, not as a hopeful candidate, but as the oath-confirmed High Priest. His place is secure, and so is ours in Him.

It is impossible for God to lie.

This truth changes how we live every day: we can stop striving to prove ourselves and start resting in the promise. In church, it means we stop treating each other like competitors and start building each other up like family anchored in the same hope. And in our communities, we become people marked by patience and courage - because we’re not waiting on shifting circumstances, but on a God who has already sworn and will not change His mind.

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