Comprehend: to take hold of with the understanding, that is, to conceive in the mind, to become cognizant of; to understand; to recognize; to consider.
To know or learn with certainty. 

The Apostle Paul’s prayer for the Ephesians, which as I read the Scripture would include me by God’s good pleasure, was this:

“that Christ may dwell in your hearts through faith; that you, being rooted and grounded in love, may be able to comprehend with all the saints what is the width and length and depth and height—to know the love of Christ which passes knowledge; that you may be filled with all the fullness of God”. (Eph 3:17-19)

Here we have three verses of inspired scripture, which give us this desire and prayer of Paul’s for the saints of God. It is God's desire for us that we come to KNOW His love through the love of His Son, Christ. The book of Ephesians is one of my very favorite books in the NT as it gives me such comfort to know the things that the Spirit reveals to me in this book. If you take just these three verses, you can search and search the Word for hours to begin to understand these dimensions; the width, the length, the depth and the height of the love of Christ. 

The Spirit reveals the love of God in Christ Jesus to us in the fullness of His Gospel, the good news of Christ. It is the greatest love ever we will know and Paul expressly desires that we be rooted and grounded in it. We come to know of His love and that without His loving us first we would not be able to love Him. Although we can never fully comprehend His immense suffering for His people we can know that He was despised and rejected of men and as our Substitute was stricken, smitten of God and afflicted. He justified His people for He bore our iniquities; they were laid upon Him, the Spotless Lamb. 

As we continually meditate on the Scripture and grow in our understanding the knowledge of this love grows and we have a lively sense of it. We begin to comprehend that once He purged our sins He sat down on the right hand of the Majesty on high and there we are with Him, for we are in Him. The depth of this love is raising a lowly sinner dead in trespasses and sins to a new creature in Him, one day to dwell with Him in Glory. The length of this love is from timeless eternity, for we are loved with an everlasting love and the breadth, the extent is from time beginning and manifested to all the elect in all ages. It is never ceasing and unchanging to His own and nothing can separate us from it, nothing. Not anguish, nor persecution, not today or anything this is to come, nothing. 

We have a just a small taste of this love here as we sojourn, it isn’t a perfect knowledge yet but the Apostle Paul desires that we grow in it and that we be filled with the fullness of God. The fullness of knowing that we have all spiritual blessings in Christ which will be fully made know to each of us when we go home and begin our everlasting communion with our Triune God.