Let's continue with the questions in the OP...
Q4. WHAT IS GOD'S GRACE FOR?
Grace is linked to mercy and peace from God the farther and from JESUS in love and truth.
2 JOHN 1:3
[3]
Grace be with you,
mercy, and
peace, from God the Father, and from the Lord Jesus Christ, the Son of the Father, in truth and love.
ROMANS 1:5 [5],
By whom we have received GRACE and apostleship, FOR OBEDIENCE TO THE FAITH among all nations, for his name.
We are to grow in God's GRACE and the KNOWLEDGE of our LORD JESUS CHRSIT.
2 PETER 3:18 But grow in grace, and in the knowledge of our Lord and Savior Jesus Christ. To him be glory both now and for ever. Amen. *
2 PETER 1:2
We do this by seeking JESUS to be our teacher and continuing in God's WORD.
JOHN 14:26 [26], But
the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatever I have said to you.
JOHN 8:31-36
[31], Then said Jesus to those Jews which believed on him,
If you continue in my word, then are you my disciples indeed;
[32], And you shall know the truth, and the truth shall make you free.
[33], They answered him,
We be Abraham's seed, and were never in bondage to any man: how say you, You shall be made free?
[34],
Jesus answered them, Truly, truly, I say to you, Whoever commits sin is the servant of sin.
[35], And the servant stays not in the house for ever: but the Son stays ever.
[36],
If the Son therefore shall make you free, you shall be free indeed.
TITUS 2:11-12 [11], FOR THE
GRACE OF GOD HAS APPEARED BRINGING SALVATION TO ALL MEN, [12], TEACHING US, THAT, DENYING UNGODLINESS AND WORLDLY JUSTS, WE SHOULD LIVE SOBERLY, RIGHTOUESLY AND GODLY IN THIS PRESENT WORLD
ROMANS 6:1-2, [1]
What shall we say then? SHALL WE SIN [break any one of God's 10 commandments], THAT GRACE MAY ABOUND? God forbid. [2], How shall we, that are dead to sin, live any longer therein?
Romans 6:15-17 What then? SHALL WE SIN BECAUSE WE ARE NOT UNDER LAW BUT UNDER GRACE? GOD FORBID! [16] Do you not know that when you present yourselves to someone as slaves for obedience, you are slaves of the one whom you obey, either of SIN RESULTING IN DEATH, or of OBEDIENCE resulting in righteousness?
God's GRACE is given to us because all of us have sinned and are sinners (broken God's 10 Commandments) and the wages of SIN is death *
ROMANS 3:23;
ROMANS 5:12;
ROMANS 6:23.
ROMANS 8:3-4 [3], For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: [4],
THAT THE RIGHTOUESNESS OF THE LAW MIGHT BE FULFILLED IN US WHO WALK NOT AFTER THE FLESH BUT AFTER THE SPIRIT.
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WORD MEANINGS OF GRACE
GRACE GREEK WORD
χάρις; charis khar'-ece From G5463; graciousness (as gratifying), of manner or act abstract or concrete; literal, figurative or spiritual; especially
the divine influence upon the heart, and its reflection in the life; including gratitude): - acceptable, benefit, favour, gift, grace (-ious), joy liberality, pleasure, thank (-s, -worthy).
GRACE HEBREW WORD
חן; chên khane From H2603; graciousness, that is, subjectively kindness,
favor or objectively (beauty): -
favour, grace (-ious), pleasant, precious, [well-] favoured.
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CONCLUSION: Grace is unmerited favour leading to a change of behaviour. God's GRACE IS FOR OBEDIENCE to GOD'S WORD in those who BELIEVE and FOLLOW it to save us from our sins and their penalty and sinful nature through our LORD JESUS CHRIST!
Hope this helps.