Grace is an important Christian concept. (See here for the Wikipedia article on Divine Grace.)
A search of the on-line English Standard Version Bible initially turns up 171 hits if I search for "grace." Of these, 47 are in the Old Testament, which means, of course, that most of the occurrences are in the New Testament.
The disparity between the Testaments is even greater, however. A simple search for "grace" also finds "disgrace," and variations of it. Of the 47 hits in the Old Testament, 36 are for "disgrace," and a few are for "graceful," which means that there isn't much mention of "grace," as such, in the Old Testament.
"Grace" as a word, is in the Old Testament as follows:
Esther 2:17 says that Esther found grace in the eyes of the king, her future husband.
Psalm 45:2 says that grace is poured upon the king's lips. (A possible reference to Christ?)
In Psalm 86:6, I find what seems to be the first legitimate request for God's grace, and the first mention of His grace in the Bible, in this pleading psalm of David.
Proverbs 3:34 uses "favor," referring to God's favor, and both the ESV and the New International Version have a text note, indicating that "grace" is a possible alternate reading.
Jeremiah 31 speaks of God's love for the people of Israel, and mentions that they found grace when wandering through the wilderness.
I make no claim to understanding of the meaning of Zechariah 4:1-7, but it seems to include a mention of God's grace.
Zechariah 12:10 also prophesies of God's grace to come.
Thus, I find but five occurrences of the word "grace," referring to God's grace, in the Old Testament.
It is not surprising that Grace is a mainly New Testament concept. John 1:17 says:
17 For the law was given through Moses; grace and truth came through Jesus Christ. (All scripture quotations are from the ESV)
Here are some of the other places where "grace" is found in the New Testament:
There's a contrast between our inheritance from Adam and Eve, and our inheritance in Christ, in
Romans 5:12 Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned— 13 for sin indeed was in the world before the law was given, but sin is not counted where there is no law. 14 Yet death reigned from Adam to Moses, even over those whose sinning was not like the transgression of Adam, who was a type of the one who was to come.
15 But the free gift is not like the trespass. For if many died through one man's trespass, much more have the grace of God and the free gift by the grace of that one man Jesus Christ abounded for many. 16 And the free gift is not like the result of that one man's sin. For the judgment following one trespass brought condemnation, but the free gift following many trespasses brought justification. 17 For if, because of one man's trespass, death reigned through that one man, much more will those who receive the abundance of grace and the free gift of righteousness reign in life through the one man Jesus Christ.Although grace is free, and covers sin, we must not go on sinning, says Paul, in Romans 6:1 What shall we say then? Are we to continue in sin that grace may abound?
and, the same chapter:
14 For sin will have no dominion over you, since you are not under law but under grace.
1 Peter reminds us that our service to others is also part of God's grace:
10 As each has received a gift, use it to serve one another, as good stewards of God's varied grace . . .
"Grace be with you," or a variation of that, is common in the New Testament. Perhaps the most significant of those statements is the last verse in the Bible:
Revelation 22:21 The grace of the Lord Jesus be with all. Amen.
Grace be with you. Thanks for reading.