The central teaching of Christianity is the Gospel. This theological statement has tremendous bearing on everything else we do. Is man basically good or basically evil? How you answer that question will influence your view of raising children, authority, government, etc. Is God’s favor given by grace or merit? How you answer that question will affect your marriage, when someone cuts you off in traffic, etc. Before we can look at anything, we must look at the Gospel.
What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin; As it is written, There is none righteous, no, not one: There is none that understandeth, there is none that seeketh after God. They are all gone out of the way, they are together become unprofitable; there is none that doeth good, no, not one. Their throat is an open sepulchre; with their tongues they have used deceit; the poison of asps is under their lips: Whose mouth is full of cursing and bitterness: Their feet are swift to shed blood: Destruction and misery are in their ways: And the way of peace have they not known: There is no fear of God before their eyes. Romans 3:9-18
The Gospel begins with an infinitely good God and a completely depraved mankind. It does not matter whether you were born a Jew or a Gentile, you were born a sinner. You will seek everything but God. No human being will seek God.
This idea of human depravity will affect your view of everything else. For example, many churches look to men for innovative ideas. Romans 3 teaches that man’s idea are at odds with God’s. We cannot rely on our own ideas for anything. We cannot trust any branch of government to define evil because depraved men will call good evil and evil good. We must understand the nature of man if we are going to make sense of anything else in our world.
There is a way which seemeth right unto a man, but the end thereof are the ways of death. Proverbs 14:12
The heart is deceitful above all things, and desperately wicked: who can know it? Jeremiah 17:9
Human beings cannot be trusted. We cannot even trust our own hearts, much less the heart of someone else.