In 1656 John Owen famously wrote in the preface of his penetrating work, Of Mortification of Sins in Believers that the chief end in his life was to promote personal holiness - a goal attested to by David Clarkson in Owen's funeral sermon in 1683. In his preface, Owen wrote,
Owen made similar comments throughout his life. For example, in 1677 Owen wrote a similar comment in a prefatory note to Patrick Gillespie's The Ark of the Covenant Opened: or, A Treatise of the Covenant of Redemption between God and Christ, as the foundation of the covenant of Grace. Patrick Gillespie was the younger brother of George Gillespie, one of the Scottish delegates to the Westminster Assembly. This work was the second of an intended five volume series on federal theology. Although, only this volume and the first remain. In his "To the Reader," Owen succinctly (!) states, "The whole design and end of my self…is to promote the knowledge of the truths of the gospel of our Lord Jesus Christ, and the practise of them."
Owen thought that theology should always be seen as "truth that is after godliness" - no matter how complex the doctrine. In his preface to Gillespie's work, Owen reflects on the vital importance of the Covenant of Redemption not only for a proper understanding of the gospel but also for the Christian life. "For the doctrine hereof [the Covenant of Redemption], or the truth therein, is the very centre wherein all the lines concerning the grace of God and our own duty do meet; wherein the whole of religion doth consist."
For Owen, doctrine was never a matter of idle speculation but a matter of communion with the triune God of the Scripture.