Many Christians lose the assurance of their secure position in the Savior’s kingdom by trusting that, to one degree or another, their dearly-loved status with God depends on what they do. The great Lutheran theologian, Martin Chemnitz (1522–86), discourages us from trusting in anything we do to guarantee God’s love. Rather, he points out from Scripture, we can only be saved by grace. That is the good news, the gospel, Jesus alone has won for us. Chemnitz writes:
The gospel speaks of righteousness, salvation, and eternal life. [But] the law of Moses clearly says in Deuteronomy 30:19, “I have set before you life and death, blessing and cursing.” (Compare Romans 7:10, “I found that the very commandment that was intended to bring life actually brought death.
These statements must not be understood as applying only to the concerns of this life. In Luke 10:25ff., the scribe says, “What must I do to inherit eternal life?” Christ replies, “What is written in the Law? … Do this and you will live.”
Therefore, what is the difference between the doctrine of the law and that of the gospel? …The law sets forth righteousness, salvation, and eternal life, to be sure, but on the condition that “the person who does these things will live by them” (Romans 10:5; also consider Matthew 19:17; Luke 10:28; and Romans 2:13).
Therefore it is the heart of the doctrine of the law that good works are necessary for salvation, so that without them it is impossible for a person to be saved. This is impossible for the law in that “the law was powerless” (Romans 8:3). [Instead the law’s] “ministry... brought death” (2 Corinthians 3:7).
The gospel offers us righteousness, salvation, and eternal life apart from our works, freely, for the sake of the obedience of the Son of God our Mediator, to be received by faith alone. [Consider] Romans 4:5, “To the one who does not work but trusts God who justifies the ungodly, their faith is credited as righteousness” and Galatians 3:22, “Scripture has locked up everything under the control of sin, so that what was promised, being given through faith in Jesus Christ, might be given to those who believe.”