Exodus 34:6 And the Lord passed by before him, and proclaimed, The Lord, The Lord God, merciful and gracious, longsuffering, and abundant in goodness and truth, 7 Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation.
(Also Number 14:18)
The name of the Lord, His character, all that He is summarized here as well as Psalm 86
Psalm 86:15 But thou, O Lord, art a God full of compassion, and gracious, longsuffering, and plenteous in mercy and truth.
He is the Lord
Gen 2:4 These are the generations of the heavens and of the earth when they were created, in the day that the Lord God made the earth and the heavens,
Gen 1:6 For the Lord knows the way of the righteous: but the way of the ungodly shall perish.
Rev 11:15 And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
He is Merciful, or full of mercy
Psalm 145:8 The Lord is gracious, and full of compassion; slow to anger, and of great mercy.
Prov 14:21 He that despises his neighbor sins: but he that hath mercy on the poor, happy is he.
Heb 4:16 Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.
1Pe 1:3 Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead,
He is gracious or full of Grace
John 1:14 And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.
1Pe 2:3 If so be ye have tasted that the Lord is gracious
He is longsuffering
Ron 2:4 Or despisest thou the riches of his goodness and forbearance and longsuffering; not knowing that the goodness of God leadeth thee to repentance?
He is abundant in goodness and truth
The word for goodness here is also translated kindness or lovingkindness as well as mercy
Psalm 5:7 But as for me, I will come into thy house in the multitude of thy mercy: and in thy fear will I worship toward thy holy temple.
Psalm 25:6 Remember, O Lord, thy tender mercies and thy lovingkindnesses; for they have been ever of old.
1Sam 12:24 Only fear the Lord, and serve him in truth with all your heart: for consider how great things he hath done for you.
Jer 10:10 But the Lord is the true God, he is the living God, and an everlasting king: at his wrath the earth shall tremble, and the nations shall not be able to abide his indignation.
He keeps mercy
1Chr 16:34 O give thanks unto the Lord; for he is good; for his mercy endureth for ever.
Prov 16:6 By mercy and truth iniquity is purged: and by the fear of the Lord men depart from evil.
He forgives
Psalm 130:3 If thou, Lord, shouldest mark iniquities, O Lord, who shall stand? But there is forgiveness with thee, that thou mayest be feared.
Eph 1:7 In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;
He will not clear the guilty, Sin still has its effects even unto the third generation
1Cor 11:27 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord.
Rom 3:19-20 Now we know that what things soever the law saith, it saith to them who are under the law: that every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.
Rom 6:15-16 What then? shall we sin, because we are not under the law, but under grace? God forbid. Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness?
