Though Spurgeon wasn’t a seminary-trained preacher, he wasn’t deficient when it came to theology. Every since he could read he spent extensive time studying the Scriptures and reading anything he could get his hands on, specifically works from the Puritans. He had no problem quoting at length from the Bible or any other work he read.
Through his studies Spurgeon had developed certain understandings of the Scriptures. His understandings had brought about conflict on many different fronts. Some of the conflicts were a result of his youthfulness (he was preaching to thousands around age 20), but many others were a result of his Calvinism. He would be attacked in the press rather harshly from the Arminians and the hyper-Calvinist. The Arminians would put vast amount of emphasis on human responsibility, while the hyper-Calvinist would take divine sovereignty to unbiblical extremes.
Here is how Dallimore describes Spurgeon’s Calvinism,
In sermon after sermon during his first years in London he asserted the doctrines of human depravity and divine election, and he did so with strong emphasis and much instruction. “My daily labour,” he stated, “is to revive the old doctrines of Gill, Owen, Calvin, Augustine and Christ.”
Spurgeon spoke out against the unthinking manner in which some Calvinist talk about a “limited atonement.” He much preferred the term “particular redemption”—the belief that Christ did not merely make salvation possible and leave it to man to do the rest, but that He accomplished the redemption of each of His elect ones and thus assured their salvation.
But although he declared “Salvation is of the Lord!” Spurgeon also preached “Whosoever will may come.” Into the New Park Street Chapel and into Exeter Hall came hundreds of men and women who did not know the Lord. In virtually every sermon he pleaded with them to recognize their lost condition, to know that Christ could save them, and to believe on Him and then and there. His preaching abounded with the free offer of the gospel to all mankind and was fruitful in the conversion of a great number.
Spurgeon recognized that the two concepts seemed contradictory. But he declared the Scripture taught both—that God would save His elect ones, but also that man was responsible concerning his soul. Therefore he constantly urged, “Believe on the Lord Jesus Christ, and thou shalt be saved.”
This free offer of the gospel to all who would believe brought upon Spurgeon the attack of the hyper-Calvinists.
Spurgeon: A New Biography by Arnold Dallimore, 67-68