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. (Hebrews 6:17–18)

God is not inconsistent. He does not exert himself with promises, and oaths, and the blood of his Son, simply to anchor down one end of our security while leaving the other to dangle in the air.

The salvation Jesus obtained by his blood was everything it takes to save his people, not just part of it.

So, we are prone to ask, Why does the writer encourage us to hold fast to our hope (Hebrews 6:18)? If our holding fast was obtained and irrevocably secured by the blood of Jesus — which it was (that’s the difference between the new covenant and the old) — then why does God tell us to hold fast?

The answer is this:

• What Christ bought for us when he died was not the freedom from having to hold fast, but the enabling power to hold fast.
• What he bought was not the nullification of our wills as though we didn’t have to hold fast, but the empowering of our wills so that we want to hold fast.
• What he bought was not the canceling of the commandment to hold fast, but the fulfillment of the commandment to hold fast.
• What he bought was not the end of exhortation, but the triumph of exhortation.

He died so that you would do exactly what Paul did in Philippians 3:12, “I press on to make it my own, because Christ Jesus has made me his own.” It is not foolishness, it is the gospel, to tell a sinner to do what Christ alone can enable him to do; namely, hope in God.

So, I exhort you with all my heart: Reach out and take hold of that for which you have been taken hold of by Christ, and hold it fast with all your might — which he mightily works in you.