“Sufficient grace” comes from 2 Corinthians 12:9 (NIV):
“But he said to me, ‘My grace is sufficient for you, for my power is made perfect in weakness.’”
This means that God’s grace is not only enough to cover our sins but also sustains us through trials, weaknesses, and limitations. His grace is complete, lacking nothing, and it empowers believers to overcome what they cannot handle in their own strength.