Even though our good works are insufficient to earn the Father's declaration that we are righteous before Him, believers are still called to serve God and neighbor by practicing good deeds (Eph. 2:8–10). As we have seen in our look at question and answer 86 of the Heidelberg Catechism, the chief reason we do good works is to thank God for His gracious salvation. Having been freed from our enslavement to sin and death, we must live in a way that reflects the freedom we have in Christ (Rom. 6). Those who keep Jesus' commandments and teach others to do likewise will be great in the kingdom (Matt. 5:19). If we love our Savior and are grateful for His redemption, we will do what He says (John 14:15).
Question and answer 86 of the Heidelberg Catechism give us other reasons for good works as well. Our good works show forth the light of Christ to unbelievers and bring praise to our Father in heaven (Matt. 5:16). We also do good works to assure ourselves that we are saved, as today's passage tells us.
In 2 Peter 1:3–11, the Apostle lists several qualities that believers must add to their faith, including knowledge, self-control, virtue, and more (vv. 3–7). We practice these godly traits not to secure our heavenly citizenship but to remind ourselves that we have been cleansed from our former sins (v. 9). We also practice these things to confirm our calling and election, and to receive a rich entrance into the eternal kingdom (vv. 10–11). Given Peter's link between believing God's promises and union with Christ (v. 4), we know that receiving a rich entrance into heaven cannot mean that our spiritual fruits secure eternal life. Instead, the Apostle means to drive home the point that true Christians act like Christians, and that the more we exhibit the fruit of the Spirit, the more we will experience the joyful confidence that we belong to the Savior. The entrance to heaven is richly provided for us in that any doubts we have regarding the state of our souls are assuaged as we see a pattern of holiness in our lives. We begin to know with certainty that we are already kingdom citizens, and we can look forward more and more to the joy of heaven. We are thus prepared to walk through the door of death unafraid because we know beyond a shadow of doubt that death will be the moment we cross the threshold into God's blessed presence.
Matthew Henry comments, "Those who are growing in grace, and abounding in the work of the Lord, shall have an abundant entrance into the joy of their Lord, and they shall reign with him for ever and ever." Although gaining assurance of salvation is not the primary reason why we do good works, we should not discount the assurance that comes as we live holy lives. As we seek to obey Christ's commands, we can be sure that He is working in us.