"When men are living in sin they go from bad to worse. At first they merely walk in the counsel of the careless and ungodly, who forget God—the evil is rather practical than habitual—but after that, they become habituated to evil, and they stand in the way of open sinners who wilfully violate God's commandments; and if let alone, they go one step further, and become themselves pestilent teachers and tempters of others, and thus they sit in the seat of the scornful. They have taken their degree in vice, and as true Doctors of Damnation they are installed, and are looked up to by others as Masters in Belial. But the blessed man, the man to whom all the blessings of God belong, can hold no communion with such characters as these.." - From Treasury of David, Pastor Spurgeon's commentary on Psalms 1
Further recommended reading & listening:
The Best of The Daily Spurgeon
The Forgotten Spurgeon, by Iain Murray
A Defense of Calvinism - by Charles Spurgeon