Do we need to believe in God’s grace alone to be saved?

from the old testament

• Israel's continual failure to keep the Law God had given them through Moses showed how much they (and we) need a Savior (Exodus 32:7–8; Judges 2:11–13; Nehemiah 9:26).
• God, of course, knew Israel would fail (Deuteronomy 31:20–21) and promised a "new covenant" in which He would put His "law within them, and . . . will write it on their hearts" (Jeremiah 31:31, 31:33; cf. Ezekiel 36:26-27).

from the new testament

• The true gospel is that only God's grace, through faith in His Son as Lord, saves. Paul wrote, "For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast" (Ephesians 2:8-9). No amount of good deeds brings salvation.
• The main purpose of Paul's letter to the Galatians is to correct those who claimed that salvation required works, such as circumcision. Paul write, "I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel—" (Galatians 1:6). Teaching that the "gospel" includes works for salvation distorts the true gospel (Galatians 1:7) To those who teach that false gospel, Paul says, "If anyone is preaching to you a gospel contrary to the one you received, let him be accursed" (Galatians 1:9).
• Works are a result of salvation, a fruit of the Spirit (Galatians 5:22-24), not criteria for salvation.
• Being unable to articulate the true gospel of grace doesn't exclude people from God's kingdom if they place their faith in Christ as Lord (Romans 10:9-10, 11:6).
• After Jesus' interaction with the rich young man whose heart was too tied to his possessions to follow Christ, the disciples ask Jesus, "Who then can be saved?”  (Matthew 19:25). Jesus replies, "With man this is impossible, but with God all things are possible" (Matthew 19-26). Those who are relying on their works to be saved are placing their hope in the impossible.
• The thief on the cross didn't earn the promised "paradise" but was saved because of his faith in Christ (Luke 23:42-43).

implications for today

Peanut butter tastes better with jelly, macaroni is even more delicious with cheese, and rice is twice as nice with beans. Some things are better when we add more to them.

But the gospel isn't one of those things. We are saved by God's grace through faith in Christ alone—not grace plus works.

The more ignorant we are of that truth, the more we're likely to fall into legalistic beliefs. That's because before we know Christ, pride in self guides us. (After all, we're so much better than "them"). But Jesus said, "No one is good except God alone" (Mark 10:18). The truth is like the fluorescent light in a clothing store dressing room: it has a way of exposing our flaws. The more we realize God's holiness, the more we understand Isaiah's reaction when he glimpsed it: "Woe is me! For I am lost; for I am a man of unclean lips, and I dwell in the midst of a people of unclean lips; for my eyes have seen the King, the Lord of hosts!” (Isaiah 6:5).

If you're still prone to thinking you're scoring points in heaven with good works, open the Bible. Study it daily. Reflect on its truths. You'll find yourself more grateful each day that you're saved by grace alone.