The quest for full assurance of salvation has long plagued the people of God. Many Christians place their faith in Christ alone for redemption but still live with doubts about their standing before God. For these dear saints, the tension between doubt and assurance can be crippling.

A crisis of doubt can happen to any follower of Christ. Even the mightiest of preachers can lack assurance. John Owen once confessed to a colleague his own struggles with assurance of God’s forgiveness. “I myself preached Christ some years,” he admitted, “when I had but very little, if any, experimental acquaintance with access to God through Christ.” Although he preached Christ, he felt little of Christ in his life. But after a season when his soul was “oppressed with horror and darkness,” Owen said things began to change when “God graciously relieved my spirit by a powerful application” of Psalm 130.

For Christians who are shaken by doubt, few passages in the Bible are as stabilizing as Psalm 130. As Charles Spurgeon notes, the psalmist climbs from “the depths of anguish to the heights of assurance.” The psalm typifies the experience many believers face when confronted with uncertainty about their faith. At least four points of application can be drawn from this text concerning the nature of doubt and assurance.

First, the depths of doubt. “Out of the depths I cry to you, O LORD! O Lord, hear my voice! Let your ears be attentive to the voice of my pleas for mercy!” (vv. 1–2). Doubt concerning one’s standing before God can sink even the most mature Christian into an abyss of discouragement. This kind of spiritual doubt may arise for a number of reasons. Perhaps, as a result of studying Scripture or sitting under faithful preaching, your conscience has been convicted of patterns of sin in your life. Maybe you are enduring trials that have caused your confidence in God’s provision to be rattled. It is also possible that your doubt is the result of unbelief and a lack of trusting in God’s promises. In times such as these, we must be reminded that the Lord of heaven and earth delights to bend down to hear the cries of His people. His mercy reaches into the abyss. So from the depths of woe, to borrow from Martin Luther’s paraphrase of this psalm, we raise our voices of lamentation, knowing that He hears our supplications.

Second, the paralysis of doubt. “If you, O LORD, should mark iniquities, O Lord, who could stand? But with you there is forgiveness, that you may be feared” (vv. 3–4). The discovery of indwelling sin accompanied with an understanding of what that sin deserves is an unnerving experience. If God demands “clean hands and a pure heart,” one look at our hands and hearts will reveal that none of us is qualified to “stand in his holy place” (Ps. 24:3–4). The only way to ascend the Lord’s holy hill is through the gateway of His forgiveness. Psalm 130:3–4 functions much as Romans 7–8 does for the Apostle Paul. Verse 3 encapsulates the crushing weight we feel under the guilt of our sin before a holy God. Verse 4 expresses the freedom we have to approach God not on the basis of personal merit but divine forgiveness. Only the grace of God can liberate us from the spiritual paralysis wrought by our guilt.

“Faith’s discovery of forgiveness in God,” Owen reminds us, “is the great supportment of a sin-perplexed soul.”

Third, the delay of assurance. “I wait for the LORD, my soul waits, and in his word I hope; my soul waits for the Lord more than watchmen for the morning, more than watchmen for the morning” (Ps. 130:5–6). The psalmist recognizes that his hope rests not in himself but in God’s Word. The repetition of “watch” and “watchman” underscores the need for vigilant patience. We must actively hope in God’s Word and patiently wait for Him to comfort us. Assurance is rarely immediate. But as the watchman awaits the morning sun, so we wait for the Lord with eager anticipation.

Fourth, the hope of assurance. “O Israel, hope in the Lord! For with the Lord there is steadfast love, and with him is plentiful redemption. And he will redeem Israel from all his iniquities” (vv. 7–8). Our hope is that the covenant Lord will most certainly come to those who wait on Him. When He comes, He brings steadfast love and plentiful redemption to deliver His people from every last one of their iniquities. Hope in God transforms the psalmist’s doubt into assurance. Assurance is not essential to have faith in Christ, but it is vital for the well-being of your faith. As the Puritan Thomas Brooks observed, to have God’s grace—and to know that you have His grace—is to experience “heaven on this side [of] heaven.” The beauty of assurance is that it brings the benefits of heaven down to earth for God’s doubt-stricken people to enjoy here and now.

This article previously appeared on Ligonier.org, and is used with permission.