Many of us fight and lose against temptation because we fail to bring a specific promise from God to the battle. Our shield of faith against Satan will be small if it is only a vague hopefulness about God, and not a firm hold on what he has actually said — if his specific, living, and active words do not abide in our hearts.

John Piper writes, “A nebulous sense that God is somehow working to help us is not such a clear channel for the Holy Spirit’s power as when we have a clear, sharp sight of a specific promise” (Reading the Bible Supernaturally, 287). A nebulous sense that God is for us may feel warm enough on good days, but it feels painfully thin when trials come — and they will come.

We need a clearer, sharper, more vivid sight of God in the daily wars we fight, and his promises paint with that kind of detail and life.

The Power of a Specific Promise

Realizing that God has given us specific promises for particular sorrows and struggles was a massive discovery for me in the fight to kill my sin and walk well with Jesus.

“Even one specific word from God can make you far more dangerous on the battlefield for your soul.”

Has anxiety crawled into our minds — about life, about family, about work, about ministry? We can remember Jesus said, “Look at the birds of the air: they neither sow nor reap nor gather into barns, and yet your heavenly Father feeds them. Are you not of more value than they?” (Matthew 6:26). Has lust vied for our attention? We can rehearse the wonder of this reward: “Blessed are the pure in heart, for they shall see God” (Matthew 5:8). Are we tempted to withhold forgiveness from someone who has hurt us? We can call to mind the inconceivable mercy (and serious warning) in Jesus’s promise, “If you forgive others their trespasses, your heavenly Father will also forgive you, but if you do not forgive others their trespasses, neither will your Father forgive your trespasses” (Matthew 6:14–15).

If you’ve fought temptation without having committed at least a few verses like these to memory, you have probably felt like you parachuted into war with only a hope and a prayer (and a parachute). From experience, I can tell you that even one specific word from God can make you far more dangerous on the battlefield for your soul.

You will eventually need more than one, but I want to plant at least one that has felt like a fresh layer of armor over the last several months. Charles Spurgeon says of these five words, “This is the masterpiece of all the promises; its enjoyment makes a heaven below and will make a heaven above.” Come and commit a masterpiece to memory.

Our Heaven Below

What promise makes a heaven wherever it goes? Spurgeon goes on to say, “Here is a deep sea of bliss, a shoreless ocean of delight; come, bathe your spirit in it; swim an age, and you shall find no shore; dive throughout eternity, and you shall find no bottom: ‘I will be their God.’”

If you’re like me, this was not the first verse that came to mind when I first read “the masterpiece of all promises.” But the longer we think over this promise — the more we wade out into the waves of this mercy — the more stunning it becomes. The words are short and familiar enough for a two-year-old, and yet no one dies having reached the bottom of this ocean or the height of this heaven. Even when we have spent ten thousand years wandering the new creation with God himself, we will still wonder that he is ours and that we are his.

“Every good we receive has its roots in one extravagant promise: ‘I will be their God’ — and in Christ, your God.”

If we have lost the ability to swim in this promise, it’s likely because we have been thinking too much on ourselves and not enough on God. We have not let ourselves be lost enough in “the depth of the riches and wisdom and knowledge of God” (Romans 11:33). Again, likely because we have thought too long and too hard about ourselves — our needs, our trials, our work, our desires, our relationships, us. In our desperate search for clarity, comfort, and control, we forget how awesomely unsearchable our God is — the God who works for those who wait for him (Isaiah 64:4).

That word — God — gives the other four words in this promise their grandeur. His sovereign power and infinite wisdom and unrivaled creativity and scandalous love and unrelenting justice and inexhaustible compassion and mercy — his God-ness — make any of his promises beautiful and trustworthy, but especially this one: “I will be their God.” Your God.

‘I Will Be Their God’

God first made this promise to Abraham and his offspring.

I will establish my covenant between me and you and your offspring after you throughout their generations for an everlasting covenant, to be God to you and to your offspring after you. And I will give to you and to your offspring after you the land of your sojournings, all the land of Canaan, for an everlasting possession, and I will be their God. (Genesis 17:7–8)

And if you believe in Christ, you are Abraham’s offspring, an heir of all God’s promises (Galatians 3:7, 29). “For all the promises of God find their Yes in him” (2 Corinthians 1:20). God now says to you, in Christ, “Fear not, for I am with you; be not dismayed, for I am your God; I will strengthen you, I will help you, I will uphold you with my righteous right hand” (Isaiah 41:10).

When God announced the new covenant, the one he would purchase for us with the blood of Christ, he repaints the masterpiece, with even more color and detail:

They shall be my people, and I will be their God. I will give them one heart and one way, that they may fear me forever, for their own good and the good of their children after them. I will make with them an everlasting covenant, that I will not turn away from doing good to them. And I will put the fear of me in their hearts, that they may not turn from me. I will rejoice in doing them good, and I will plant them in this land in faithfulness, with all my heart and all my soul. (Jeremiah 32:38–41; see also Jeremiah 31:31–34; Ezekiel 37:21–28)

I will make a covenant with them. I will only ever do good to them. I will renew their dead and lifeless hearts with holy fear. I will rejoice in loving them. I will plant them where I am — forever secure, well-fed, and fruitful — “with all my heart and all my soul.” Jesus bled and died to bring you to this God (Luke 22:20; 1 Peter 3:18). In him, “You are a chosen race, a royal priesthood, a holy nation, a people for his own possession” (1 Peter 2:9).

Every good we receive has its roots in one extravagant promise: “I will be their God” — and in Christ, your God.

The Heaven Ahead

When God knit together this great promise and gave it to Abraham in the very beginning, he knew it would also be the final and never-ending note of history. When every fiber of anxiety, lust, and pride finally falls away from us, and God makes all things new, we will wade into an ever wider and deeper ocean:

Behold, the dwelling place of God is with man. He will dwell with them, and they will be his people, and God himself will be with them as their God. He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain anymore, for the former things have passed away. (Revelation 21:3–4)

“God is now our God, but not in the way he will be.”

If we fail to see the wonder in “I will be their God,” we will not hunger for heaven. We will put off thoughts of the paradise to come, suspecting it will be something less than what we’ve had. But all that we have now is only a refreshing pitcher of cold water compared to that deep sea of bliss. God is now our God, but not in the way he will be (1 Corinthians 13:12).

Heaven is not heaven because our loved ones are there, or because tears are wiped away, or because all is made new — glorious as these things are. Heaven is heaven because of these five words: “I will be your God.”

Live Up to Your Privileges

Spurgeon marries the wonder of the promise with the weight of urgency when he writes,

This is the masterpiece of all the promises; its enjoyment makes a heaven below and will make a heaven above. Dwell in the light of your Lord, and let your soul be always ravished with His love. Get out the marrow and fatness that this portion yields you. Live up to your privileges, and rejoice with unspeakable joy.

If God is with you and for you, though you did nothing to deserve or earn his promises, do everything you can to live up to their privileges. “Let your manner of life be worthy of the gospel of Christ” (Philippians 1:27).

The apostle Paul sounds the same note when he rehearses the promise “I will be your God.” After quoting Leviticus 26:12, he writes, “Since we have these promises, beloved, let us cleanse ourselves from every defilement of body and spirit, bringing holiness to completion in the fear of God” (2 Corinthians 7:1). Those who are saved by grace alone and given priceless, blood-bought promises by God confront every defilement and strive for complete holiness. We make every effort, by the Spirit and strength and help of God, to be found worthy.

When you hear and remember the masterpiece “I will be their God,” let your heart soar on the winds of his glory, put to death whatever might hinder your communion with him, and so live up to the privilege of being his.