"There is not one blade of grass, there is no color in this world that is not intended to make us rejoice."
"A dog barks when his master is attacked. I would be a coward if I saw that God's truth is attacked and yet would remain silent."
"All the blessings we enjoy are Divine deposits, committed to our trust on this condition, that they should be dispensed for the benefit of our neighbors."
"God tolerates even our stammering, and pardons our ignorance whenever something inadvertently escapes us - as, indeed, without this mercy there would be no freedom to pray."
"However many blessings we expect from God, His infinite liberality will always exceed all our wishes and our thoughts."
Found these quotes from John Calvin
HERE
Here are two of his that seem to be at odds with each other, though:
"God preordained, for his own glory and the display of His attributes of mercy and justice, a part of the human race, without any merit of their own, to eternal salvation, and another part, in just punishment of their sin, to eternal damnation."
"No man is excluded from calling upon God, the gate of salvation is set open unto all men: neither is there any other thing which keepeth us back from entering in, save only our own unbelief."
So, eventhough I would not put him in the "great" category, he was a pretty good theologian. He has influeneced many people.