Proverbs 11:18 The wicked worketh a deceitful work: but to him that soweth righteousness shall be a sure reward.
The promise of a sure reward is consequent to the sowing of righteousness. If you sow righteousness, then there will be a sure reward for you. We “sow righteousness” when we live out in real life the righteousness that is already in us by grace, that is, when we do the good works for which we were created in Christ, when we are kind, loving, merciful, forgiving, etc.
The promise of reward is for our encouragement to continue doing good. Every good deed, every kind act, every word of blessing has an eternal reward. And the Lord is keeping track. Jesus says, for example: “Whoever gives one of these little ones even a cup of cold water because he is a disciple, truly I say to you, he will by no means lose his reward. [Matthew 10:42]”
We don’t do good works for the rewards, but we do have the promise that a reward is coming. No kind word or deed is wasted in God’s accounting. Therefore we “sow righteousness” whether we see a reaping right away or not. Just as God has created us in Christ Jesus for good works, so we can be sure that He will use us to sow a little bit of God’s life into the world for the blessing of others.
We do these acts of kindness because He first loved us, and the added blessing is that there is a sure reward for each one. Who knows how many and how great are the rewards stored up for us in eternity? The greatest reward, of course, is the forgiveness of sins, eternal life, and salvation. And along with it comes innumerable sure rewards. But remember, these are rewards of grace. Our work does not earn a reward, but God’s work grants it.