The Faithful Promise Keeper: Mary’s Song of God’s Mercy

This devotional expands on Day 2 of the free 7-Day guide “Journey through Hope”, exploring how God’s faithfulness to His promises throughout history culminates in the coming Messiah.

A Song Rooted in History

When Mary sang these words, she was reflecting on centuries of God’s faithfulness—a pattern of promise-making and promise-keeping that stretched from Eden to her own moment of divine encounter. Throughout Scripture, God has promised many things, both merciful and sobering. And throughout human history, He has proven Himself a faithful promise keeper, fulfilling every word exactly as spoken.

Consider the trajectory: He promised Adam and Eve a perfect life in perfect paradise—unless they disobeyed. When they rebelled, the curse that followed was exactly what God said would happen. The work became toilsome, beauty became tainted, and death entered the world (Genesis 3:17-19). God held true to His promise even when it brought consequences. But notice—at the very same moment He pronounced judgment, He promised a future deliverer who would crush the serpent’s head (Genesis 3:15). Even in discipline, God was already planning redemption.

This is the pattern Mary recognized: God’s promises are trustworthy in both warning and hope, in judgment and mercy. He doesn’t make idle threats or empty guarantees. Every word carries weight because it comes from a faithful promise keeper who cannot lie (Hebrews 10:23).

The Promise Repeated Through Generations

This salvation—deliverance from internal darkness and enslavement to sin—was promised time and again to Abraham, David, the prophets, and many more. To Abraham, God promised descendants as numerous as the stars and that through his seed all nations would be blessed (Genesis 12:1-3). To David, He promised an eternal kingdom and a throne that would never end (2 Samuel 7:12-16). Through the prophets, He promised a Suffering Servant, a Prince of Peace, a Light to the nations.

Each promise pointed to the same ultimate reality: if His people would just believe and be faithful to Him, He would send them deliverance. Not primarily from political oppression or earthly enemies—though they often misunderstood it that way—but from the deeper captivity that truly enslaved them. God was promising to free them from their internal darkness, from sin’s dominion, from the spiritual death that separated them from their Creator.

Mary recalls this long history of promises in her song of praise, telling of God’s continued mercies, deliverance, and faithfulness to fulfill all He had spoken to His people. She understood that the child growing in her womb was the culmination of every promise God had ever made—the answer to centuries of faithful waiting.

A Faithful Promise Keeper Who Remembers

Notice Mary’s phrase: “in remembrance of His mercy.” This doesn’t mean God had forgotten and suddenly recalled His promises. Rather, it means He was actively bringing to fulfillment what He had always intended. The Hebrew concept of “remembering” involves action—when God remembers, He acts on what He knows. He was about to demonstrate His character as a faithful promise keeper in the most profound way imaginable.

His greatest promise—eternal deliverance and reconciliation to Himself—was about to be fulfilled down to the very last detail. Bethlehem, as prophesied. House of David, as promised. Born of a virgin, as foretold. Even the future rejection and suffering of the Messiah had been woven into the ancient promises, though few understood those threads until after they were fulfilled.

This is what separates the God of Scripture from human beings who make promises they can’t keep or from false gods who demand worship but deliver nothing. Our God doesn’t just intend to fulfill His word—He orchestrates history itself to ensure every promise comes to pass exactly as spoken. Nothing is forgotten. Nothing is abandoned. Every word He has spoken will be accomplished (Isaiah 55:11).

Why This Matters for Us

We live in a world where promises are routinely broken. Political leaders promise change and deliver disappointment. People promise faithfulness and abandon commitments. We even break promises to ourselves. In such a world, the concept of a faithful promise keeper can feel almost mythical—too good to be true.

But Mary’s song reminds us that God’s track record spans millennia, and it’s flawless. Every promise of judgment came to pass. Every promise of mercy was fulfilled. And every prophecy about the Messiah—from His birthplace to His betrayal—happened precisely as predicted. If God kept His promises through centuries of waiting, through Israel’s repeated unfaithfulness, through periods of prophetic silence, why would He stop now?

The promises that matter most to us today are still rooted in His character as a faithful promise keeper. He promised never to leave us or forsake us (Hebrews 13:5) and that all things work together for good for those who love Him (Romans 8:28). He also promised that nothing can separate us from His love (Romans 8:38-39). And just as He fulfilled His promise to send the Messiah the first time, He will fulfill His promise to send Him again.

The Promise About to Be Fulfilled

Mary stood at a unique moment in salvation history—the cusp of fulfillment. For centuries, God’s people had been waiting for the light, trusting in promises that seemed impossibly distant. Now, in her womb, the faithful promise keeper’s greatest work was taking shape. Within weeks, the Word would become flesh. The Light would enter the darkness. The Deliverer would be born.

She couldn’t have known all the details of how it would unfold—the manger and the cross, the rejection and the resurrection, the suffering and the glory. But she knew enough: God was keeping His word. God was acting “in remembrance of His mercy,” bringing to completion what He had planned from the foundation of the world.

As we move deeper into this Season, we stand in a different position than Mary. We know how the story unfolded. We’ve seen the promises fulfilled in Christ’s first coming. And that perfect track record gives us confidence as we wait for promises yet to come—His return, our resurrection, the restoration of all things. The same God who kept every promise about the first coming will keep every promise about the second.

God is not finished yet. But His history assures us: He will finish what He started. Every promise will be kept. Every word will be fulfilled. We can trust Him completely because He has never—not once in all of human history—broken His word.

Reflection Questions

1. Which of God’s promises do you find hardest to trust right now? How does His track record of faithfulness throughout Scripture strengthen your confidence?
2. How does understanding that God’s promises consistently point to internal/spiritual deliverance (not just external comfort) change what you’re asking Him for?
3. Mary praised God for “remembering His mercy” when she saw His promises coming to fulfillment. Where do you need to recognize and praise God’s faithfulness in your own life?
4. What difference does it make to know that the same God who fulfilled every detail of prophecy about Christ’s first coming will be equally faithful to His promises about the future?

Prayer

Consider God’s faithfulness to His promises throughout all of Scripture and history. Thank Him for being a faithful promise keeper who remembers His mercy and fulfills every word He speaks. Ask Him to help you trust His promises even when fulfillment seems distant.

If you’d like to keep reflecting throughout the week, you can download my 7-day guided devotional and read it at your own pace.