God gives us grace "not to sin", the grace is not there to allow sin, but to give us freedom from it. When we do sin, the grace is extended to us as forgiveness for those who confess their sin and desire to be freed from it. Those who claim we can sin without consequences because of grace, have forgotten the scripture that tells us what God does when believers sin.
Hebrews 12:5-7 "…5 And you have forgotten the exhortation that addresses you as sons: “My son, do not make light of the Lord’s discipline, or lose heart when He rebukes you. 6 For the Lord disciplines the one He loves, and He chastises everyone He receives as a son.” 7 Endure suffering as discipline; God is treating you as sons. For what son is not disciplined by his father?…"
Often the excuse, "we are under grace" is spoken to justify sin, these people are not forgiven of their sin because rather than confessing it they brag about it and excuse it.
God will discipline His children until they come to this place of confession.
