2 Corinthians 5:20 – 6:2, “Now then, we are ambassadors for Christ, as though God were pleading through us: we implore you on Christ’s behalf, be reconciled to God. For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him. We then, as workers together with Him also plead with you not to receive the grace of God in vain. For He says: “In an acceptable time I have heard you, and in the day of salvation I have helped you.” Behold, now is the accepted time; behold, now is the day of salvation.””
For this phrase to make sense, we must first understand God’s grace. Ephesians 2:8, the bibles states we have been saved by grace through faith. If you carefully read where grace shows up, you will find that it is always talking about something God does or did. In other words, God initiated it. Grace is always a God thing or idea. For the grace of God to be completed, we must respond to that grace. In Ephesians we see our response. We respond by faith.
Paul is warning the Corinthians in the verse above from responding inappropriately. The end of chapter 5, Holy Spirit through Paul tells them what God did, Grace. In chapter 6, Holy Spirit warns them not to miss the opportunity by not responding in Faith. The word vain means empty or lack of fruit. Holy Spirit is literally telling them to not come out empty handed. We receive the grace of God, by us having faith in what He is doing or done.
Hebrews 4:1-2, “Therefore, since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it. For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, not being mixed with faith in those who heard it.”
Once again Holy Spirit is warning us here to not miss the grace of God like some people have. He goes a step further by telling us how they missed it. They missed it because they didn’t believe what God was doing.
Another way people miss the grace of God is by trying to do what God has already done in their own strength. This is the more common one. Instead of trusting God and following His lead, we follow our lead and expect God to sprinkle His grace over it.