First, I want to take a look at the three major belief systems within Christianity:
3. Roman Catholicism
All three hold to the "Apostle's Creed" (first and foremost, belief in the Trinity - except for some cases in the Arminian camp)
Arminianism: The closest thing there is to a "confession" in the broadest Arminian tradition are the "Articles of Remonstrance".
That man has not saving grace of himself, nor of the energy of his free will, inasmuch as he, in the state of apostasy and sin, can of an by himself neither think, will, nor do any thing that is truly good (such as saving Faith eminently is); but that it is needful that he be born again of God in Christ, through his Holy Spirit, and renewed in understanding, inclination, or will, and all his powers, in order that he may rightly understand, think, will, and effect what is truly good, according to the Word of Christ, John 15:5, “Without me ye can do nothing.
That this grace of God is the beginning, continuance, and accomplishment of all good, even to this extent, that the regenerate man himself, without prevenient or assisting, awakening, following and cooperative grace, can neither think, will, nor do good, nor withstand any temptations to evil; so that all good deeds or movements, that can be conceived, must be ascribed to the grace of God in Christ. but respects the mode of the operation of this grace, it is not irresistible; inasmuch as it is written concerning many, that they have resisted the Holy Ghost. Acts 7, and elsewhere in many places.
Anybody who has spent time in an Arminian church has heard "everybody has a "God-shaped-hole" in them. Basically, Arminius taught "total depravity", but believed that "total" didn't mean depraved enough that people couldn't respond to God's call of their own free will - looking for something to fill in that "God-shaped-hole".
Reformed: The Westminster Confession says, "From this original corruption, whereby we are utterly indisposed, disabled, and made opposite to all good, and wholly inclined to all evil, do proceed all actual transgressions." (Chapter IV, section 4)
Instead of saying "we all have a God-shaped-hole", I put it "God has a me-shaped-hole"- there is a place prepared in glory. Obviously, God has no need for me, or any other person; the point is that God is the one that makes the move.
(note: where I find that the confessions don't agree with the Bible, I don't agree with the confessions. The Reformed confessions and catechisms were - for the most part - written in a movement away from Rome - sometimes they went a little too far. Two examples are the sections directly before and after this section.)
Roman Catholicism: The Roman Catholic Catecism says (407) The doctrine of original sin, closely connected with that of redemption by Christ, provides lucid discernment of man's situation and activity in the world. By our first parents' sin, the devil has acquired a certain domination over man, even though man remains free. Original sin entails "captivity under the power of him who thenceforth had the power of death, that is, the devil" Ignorance of the fact that man has a wounded nature inclined to evil gives rise to serious errors in the areas of education, politics, social action and morals.
Humans remain "free", but "wounded".
Why was this important to the Reformers?
The doctrine of total depravity is also known as "man's inability". The focus on the Reformers was a call to the Scriptures as the final authority and a call to the cross of Christ as the hope of our salvation and a call to the humble acceptance of the sovereignty of God.
To teach "total depravity" meant to them that all of the glory for our salvation was due entirely to God.
Every doctrine that we add to "salvation" makes the cross smaller. Every "mediator" puts distance between us and our Lord. Every requirement that man can fulfill is one more area that Christ does not have to fill.
There is nothing that I can do (or not do) that will make my feeble attempts at righteousness more acceptable to God.
It is not who I am,
but what He has done.
It is not what I have done,
but who He is.