This was something that I found on monergism.com that I thought I would share given the amount of discussion we have had on this topic lately. I feel John Hendryx puts it very well.
Free Will Synergism Vs. Free Grace Monergism
by John Hendryx
Synergists teach '... and as many as believed were ordained to eternal life.' but The Bible teaches 'AND AS MANY AS WERE ORDAINED TO ETERNAL LIFE BELIEVED.' (Acts 13:48)
Synergists teach that 'salvation depends on human will', but the Bible teaches that 'it depends not on human will or exertion, but on God, who has mercy." (Rom 9:16)
Synergists teach '...'no one knows the Father except those who choose the Son.' But the Bible teaches that 'no one knows the Father except the Son and anyone to whom the Son chooses to reveal Him' (Matt 11:27) They are the ones who 'choose' the Son.
Synergists teach that 'All can come to Christ of their own free will', but Jesus teaches that 'no one can come to me unless it is granted him by the Father.' (John 6:65) and all whom He grants will come (John 6:37) Free Will Synergism Vs. Free Grace Monergism
Synergists teach that 'you are not Christ's sheep because you do not believe', but Jesus teaches that 'you do not believe because you are not of My sheep.' (John 10:26)
Synergists teach that 'the reason you are not of God is because you are unwilling to hear and believe God's words.' Jesus, on the other hand, taught, 'The reason why you do not hear [God's words] is that you are not of God." (John 8:47)
Synergists teach that 'salvation is so easy a cave man can do it" but the Bible teaches that "What is impossible with man is possible with God." (Luke 18:27)
In the Divine economy men are responsible to believe the gospel, but are morally impotent to do so (when drawing from their own native resources). This inability (due to our intimate solidarity with Adam's sin) is something we are culpable for, much like owing a debt we cannot repay. So God has every right to call us all to account to 'repay our debt', so to speak, even though fallen man does not have the resources to do so. The Church has a privilege and an obligation to call all men to repent and believe the gospel (an imperative) but, left to themselves, no one believes. But God, in his great mercy, still has mercy on many, opening their hearts to the gospel that that might believe.
To this sometimes a synergist often quotes "whosoever will may come" to which we reply that this quote does not teach an indicative of what we are able to do, but rather, teaches what we 'ought' to do. As Martin Luther said, "Does it follow from: 'turn ye' that therefore you can turn? Does it follow from "'Love the Lord thy God with all thy heart' (Deut 6.5) that therefore you can love with all your heart? What do arguments of this kind prove, but the 'free-will' does not need the grace of God, but can do all things by its own power...But it does not follow from this that man is converted by his own power, nor do the words say so; they simply say: "if thou wilt turn, telling man what he should do. When he knows it, and sees that he cannot do it, he will ask whence he may find ability to do it..." Luther BW,164