1 Peter 2:16 As free, and not using your liberty for a cloke of maliciousness, but as the servants of God.
God’s standard of holiness did not change even though now in the New Testament we are under grace. He is still a holy God; it is His goal for our life Ephesians 1:4, and still His standard Isaiah 62:10; 35:8-10. Grace empowers us to reach His high holy standards by imparting to us a righteous and holy nature Ephesians 4:24.
Some Christians influenced by modern philosophies (Colossians 2:8) and errant concepts of grace try to use the label “legalism” to nullify Biblically defined standards about doing good works, obedience to NT commands, separation from the world, or any outward expression of inward holiness such as modesty. A hatred of Biblical absolutes, authority, and holiness causes liberal believers to use the label “legalist” sometimes as a cover for their lawlessness. We are exhorted in 1 Peter 2:16 that as being free under grace not to use it as a cloak of maliciousness or a cloak to hide bad behavior.
Grace made us free to serve not to sin. The Apostle Paul addressed this in Romans 6:1, 2 after speaking about the abundance of grace and free gift of righteousness in Romans 5:17-21. “What shall we say then? Shall we continue in sin that grace may abound? God forbid (let it never be said; let it not be; by no means; far from it) ….” Instead of “God forbid,” we might say, “Are you kidding me,” or “C’mon man.”