Calvin, commenting on Ephesians 3:19 says of knowing the “love of Christ that surpasses knowledge”:
Almost all men are infected with the disease of desiring to obtain useless knowledge. It is of great importance that we should be told what is necessary for us to know, and what the Lord desires us to contemplate, above and below, on the right hand and on the left, before and behind. 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.