It is because of the grace of God not only that there is a gospel but that this gospel is received for what it truly is. Given that the world by its wisdom does not, and cannot, know God, we are clearly indebted to the grace of God if we have been given to understand, accept, and believe the gospel. It is the grace of God alone, and not our own natural powers, that can keep us from soul destroying errors and keep us satisfied with the truth in Christ. Whenever we reflect on our own belief of the truth we ought to give glory to God.
It is remarkable, and deeply encouraging, that John Owen continues to be read today. Recent reprints like Overcoming Sin and Temptation and Communion With The Triune God (both from Crossway) will do much good, and have been taken up with real enthusiasm (see the discussion here). However, although he ranks as one of the finest pastoral theologians in church history, Owen was also a first class polemicist.
He can not only help us today with how to live the Christian life, but also in the great and necessary work of defending the gospel and prosecuting error. Owen brings his massive learning, a titanic grasp of theology, an incredible knowledge of ancient and contemporary authors and issues, a mind filled with Scripture, the care of a pastor, and the humility of a child, to confront the great dangers that threaten to undermine and overthrow the truths of the gospel. When it came to fighting error he was, quite simply, the elite special forces.
If you have benefitted from his pastoral theology don't neglect his more polemical works. If you do neglect them you will not understand the man, and you will not be trained by a seasoned fighter in the art of godly warfare.
Here is John Owen facing the danger of the rise of Socinianism:
This I am compelled to say, that unless the Lord, in his infinite mercy, lay an awe upon the hearts of men, to keep them in some captivity to the simplicity and mystery of the gospel who now strive every day to exceed one another in novel opinions and philosophical apprehensions of the things of God, I cannot but fear that this soul-destroying abomination will one day break in as a flood upon us.John Owen, Vindicae Evangelicae, p. 42