One of Whitfield’s followers (who obviously still held great animosity against Wesley) said to Whitfield, “We won’t see John Wesley in the heaven, will we?” Whitfield humbly replied “Yes, you’re right, we won’t see him in heaven. He will be so close to the Throne of God and we will be so far away, that we won’t be able to see him!”
So, with that out of the way, let’s dig into Wesley’s quotes about Calvinism.
Q. 74. What is the direct antidote to Methodism, the doctrine of heart holiness?
A. Calvinism: all the devices of Satan, for these fifty years have done far less toward stopping the work of God, than that single doctrine. It strikes at the heart of salvation from sin, previous to glory, putting the matter on quite another issue.
1.) This shows Wesley’s weak view of God’s sovereignty, He thinks God’s work can be stopped by false doctrine, instead of false doctrine being of the decree that God has morally sufficient reasons for decreeing.
2.) Calvinism is therefore Satanic and a device of Satan by Wesley’s reasoning here. His objections also don’t follow. “It strikes at the heart of salvation from sin” Why? Because we believe Jesus actually saves his people? That He monergistically saves them without our cooperation being the ending chain conclusion? There is such a disconnect that Jesus can die for you, but only make salvation possible. Whether or not your salvation counts, whether or not Jesus took your place is in vain is based solely on your free will decision. The God of the Universe can want something and not have it. That’s Synergism in a nutshell.
And yet what are all the absurd opinions of all the Romanists in the world, compared to that one,that the God of love, the wise, just, merciful Father of the spirits of all flesh, has, from all eternity, fixed an absolute, unchangeable, irresistible, decree, that part of all mankind shall be saved, do what they will; and the rest damned, do what they can!
Again, Wesley sounds like an internet Arminian. It’s very common for Arminians to find more in common with the papists than the Reformers. How dare the Calvinist say that God isn’t dependent on the counterfactuals of creaturely freedom! How dare the Calvinist say that God can elect whoever he wills, (John 6:44) How dare the Calvinist say that God can have mercy on who he pleases (Romans 9:15), How dare we not impose our feelings and supposed ethical standards on God and tell him what he can and can’t do because otherwise, it would hurt my sensibilities. We should not reject things on emotional grounds.(1 Thessalonians 5:21)
Wesley went even further by stating
“When Satan could no otherwise prevent this, he threw Calvinism in our way.’ 
I think his statement is self-explanatory, he attributes our theology to Satan directly.
“You represent God as worse than the devil; more false, more cruel, more unjust. But you say you will prove it by scripture. Hold! What will you prove by Scripture? That God is worse than the devil”
Oh, the Irony that Wesley preaches on free grace but denies that God is free to bestow his grace on whoever he pleases! Despite the rhetoric that Calvinism is a satanic stumbling block, I see Calvinism as a theology dedicated to the glory of God, Soli Deo Gloria, the Latin term we say and live by, to God alone be the glory for actually saving his people and preserving us with his grace. God is the author and finisher of my faith, God saved me, not because he looked down the corridor of time and saw that I would choose him, but because of his mercy. God is love (1 John 4:8) but that’s not all he is, God desires to show all his attributes (Romans 9:15) I will leave you with some quotes that I believe show the beauty of Calvinism as opposed to Arminianism.
“God is under no obligation to extend his grace to the rebel sinner, and every single person who enters into eternal punishment would, were they given the opportunity, freely choose to remain under punishment rather than bow the knee in loving adoration of the God they hate.”
“As Boettner so aptly observes, for the Calvinist, the atonement “is like a narrow bridge which goes all the way across the stream; for the Arminian it is like a great wide bridge that goes only half-way across.” 
“I cannot conceive an intention in God that Christ should satisfy his justice for the sin of them that were in hell some thousands of years before, and yet be still resolved to continue their punishment on them to all eternity.” 
 Star Trek: Datalore Episode
 John Wesley: A Biography by Stephen Tomkins cited in tonycooke.org
 The works of John Wesley (Baker Book House, Grand Rapids, MI) (1996) Volume 8, p. 336
 John Wesley, Sermon 55, On the Trinity.
 John Wesley cited in The Ecclesticial Principles and Polity of the Wesleyan Methodists by William Peirce p.12
 John Wesley, Sermon 128, Free Grace
 Debating Calvinism: Five Points, Two Views p. 19 by James White and Dave Hunt
 The Five Points of Calvinism, David N. Steele p. 41
 John Owen, A Display of Arminianism, The Works of John Owen p.88