Our reluctance to teach doctrine has led to a gross misunderstanding of the grace of God because what we believe about the nature of man directly impacts our view of God's grace. So many people have a faulty understanding of their own fallen nature that they cannot hope to correctly understand grace.
The bible teaches very clearly what the nature of fallen man is like. This doctrine is known as total depravity.
Here are a few of the many passages where we see total depravity spoken of:
Formerly, when you did not know God, you were enslaved to those that by nature are not gods. But now that you have come to know God, or rather to be known by God, how can you turn back again to the weak and worthless elementary principles of the world, whose slaves you want to be once more? -- Galatians 4:8-9
We know that our old self was crucified with him in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin. Do you not know that if you present yourselves to anyone as obedient slaves, you are slaves of the one whom you obey...? But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed... For just as you once presented your members as slaves to impurity and to lawlessness leading to more lawlessness, so now present your members as slaves to righteousness leading to sanctification. For when you were slaves of sin, you were free in regard to righteousness. -- Romans 6:6,16,17,19,20
Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is a slave to sin.-- John 8:34
we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind. -- Ephesians 2:3
For the mind that is set on the flesh is hostile to God, for it does not submit to God’s law; indeed, it cannot. Those who are in the flesh cannot please God. -- Romans 8:7-8
None is righteous, no, not one; no one understands; no one seeks God. -- Romans 3:10-11
What these passages teach us about our fallen natures is that we are totally incapable of pleasing God in any way on our own. We don't seek after God, we cannot please Him or obey His law, and we are slaves to our sin. What happens all too often is that our fallen-ness is downgraded (or upgraded depending on your point of view) from "hopeless" to "pretty bad". Sure, we say, we have original sin inherited from Adam, but we aren't totally without the ability to choose Christ.
There are two problems with this downgrade of total depravity. First, it isn't true. The bible clearly teaches that we cannot choose God without His choosing us first.
The second problem is that it diminishes God's grace. God's grace is what saves us. It resurrects us from the dead spiritual state we were born into and breathes life into our souls. It turns our hearts of stone into hearts of flesh. God's grace chooses, redeems, and sustains us in Christ.
When we deny total depravity, we reduce grace to a mere shadow of itself. It becomes God's mechanism for providing a way if we will only accept it. We try to make grace understandable by giving it easy to remember definitions like "God's unmerited favor". We try to make it catchy by using acronyms like "Grace is God's Riches At Christ's Expense". These may be true as far as they go, but they don't go nearly far enough. What ends up happening is that grace becomes commonplace and normal. In our effort to mass market grace, we have made it cheap.
When we are not faithful to teach doctrines like total depravity, we rob people of their ability to appreciate the glory of God as He has revealed it to us. In our effort to make grace more accessible, we have given access to a cheap grace, a grace that is a pale, weak version of the glorious grace God reveals to us in the scriptures.