The first Doctrine of Grace, The"T" in TULIP the first of the 5 points of Calvinism. Total Depravity or Radical Depravity. Sin has had an effect on all of creation. God's Holiness Shows us how far we are from Him and How enormous is the grace of God. We see How much love there is between God and Christ. And the love that Christ has for us, this gift that God had given to Him before the foundations of the world. He came to redeem those whom the Father had given to Him. (John 17)
Lord’s Day 3
6. Did God create man thus, wicked and perverse?
No, but God created man good and after His own image, that is, in righteousness and true holiness, that he might rightly know God his Creator, heartily love Him, and live with Him in eternal blessedness, to praise and glorify Him.
 Gen 1:31;  Gen 1:26-27  Eph 4:24; 2 Cor 3:18;  Col 3:10;  Ps 8
7. From where, then, does this depraved nature of man come?
From the fall and disobedience of our first parents, Adam and Eve, in Paradise, whereby our nature became so corrupt that we are all conceived and born in sin.
 Gen 3;  Rom 5:12, 18-19;  Ps 14:2-3, 51:5
8. But are we so depraved that we are completely incapable of any good and prone to all evil?
Yes, unless we are born again by the Spirit of God.
 Gen 6:5, 8:21; Job 14:4; Isa 53:6; Jer 17:9; Jn 3:6; Rom 7:18;  Jn 3:3-5