In Christian theology, assurance means that I am sure that God saves me. The catechism (q&a 21) emphasizes that faith is not mere knowledge, but “firm confidence (or assurance)”. This statement is directly aimed at the Roman Catholic teaching that “no one can know with a certainty of faith […] that he has obtained the grace of God.” (Council of Trent, ch. 9)
But is it true that every believer has this certainty? And if you are not 100% sure that you are saved, does that mean your faith is weak? There are some Reformed church communities that focus so much on the need of assurance, that many church members despair and doubt their salvation. They make their religious feelings the basis of their faith; and those feelings often disappoint.
The Westminster Confession of Faith presents a more detailed picture. “This faith is different in degrees, weak or strong; may be often and many ways assailed, and weakened, but gets the victory; growing up in many to the attainment of a full assurance, through Christ, who is both the author and finisher if our faith.” (WCF 14.3) Jesus often told his followers that they had “little faith”; the same is true for many of us. But even if our faith is not mature enough to give us absolute certainty of our salvation, it still is faith.
Ultimately, our confidence of faith does not come from the certainty that we are being saved; but from the conviction that Jesus is indeed the generous, merciful Saviour, whose blood can cleanse even a sinner like me. Some days we may see this very clearly, and celebrate: “I belong to Jesus, my great Saviour, so I know that all is well.” Other days, we may falter, but still say: “I don’t feel certainty about my salvation; still, I throw myself on the mercy of Jesus Christ; where else could I go?”
The last section of the Canons of Dort also speaks very pastorally about faith and assurance. “Believers themselves can be certain of this preservation of the elect to salvation…” (CoD 5.9) “This assurance is not produced by a certain private revelation besides our outside the Word” (such as our feelings) “but by faith in the promises of God” (5.10). During difficult periods in their lives, they “do not always feel this full assurance of faith” (5.11); but despite this, the Lord preserves true believers by his Holy Spirit.
Our confidence about being saved is not what saves us; we should have confidence in the power of Jesus’ sacrifice for us. But we certainly may pray for, and expect, this assurance to grow in us as we live our lives for our Lord.