Calvin's Commentary on Eph 3:19
The love of Christ is held out to us as the subject which ought to occupy our daily and nightly meditations, and in which we ought to be wholly plunged. He who is in possession of this alone has enough. Beyond it there is nothing solid, nothing useful,-nothing, in short, that is proper or sound. Though you survey the heaven and earth and sea, you will never go beyond this without overstepping the lawful boundary of wisdom.