Sola fide and sola gratia, as used in the Protestant Reformation, form the basis of a God-centered Gospel; meaning that while the sinner is dead in his trespasses and sins, God Himself sovereignly regenerates those whom He will.
By His gift of grace God gives them the faith to believe in Christ, and they repent of their sins. This is actually diametrically opposed to any of the seeker-friendly quasi-evangelical movements e.g. the Purpose Driven/Seeker Driven Druckerite religion e.g. as taught by Rick Warren.
A man-centered gospel is the belief that the determining factor in whether or not a man is eternally saved, in the end, relies—at some level—upon an act of his own will i.e. human decision. This is often called synergism because it is thought to be a cooperative effort between God and man.
While a God-centered Gospel means that man has absolutely nothing whatsoever to do with causing his salvation by “choosing God,” “deciding to follow Christ,” “asking Jesus into your heart,” and/or any other like phrases so common today.
The sad fact is that the contemporary mainstream evangelical community largely believes in synergism (man cooperates with God), while in stark opposition to the synergism of apostate Roman Catholicism, the Reformers like Martin Luther (well before John Calvin) taught monergism i.e soli Deo gloria.
Yet to a great extent today the Emerging Church movement overall, and voices within this Emergent rebellion against sola Scriptura e.g. like former EC rock star “pastor” Rob Bell, also strongly believes (at best) in synergism.