Enjoying the empowering of the Spirit and the indwelling of the risen Christ their very being will be rooted and grounded in love, for love is the basis of their salvation (John 3:16; Romans 5:8; 1 John 4:9-10), the nest in which they find their rest (1 John 4:8), the goal ever set before them (1 John 4:11). And it is the love of Christ which is beyond all knowledge. It is something that is so vast that its breadth, length, height and depth will take all the people of God through all ages to fathom. And being filled with that love we will be filled with all the fullness of God, thus becoming the fullness of Him Who fills all in all (Ephesians 1:23).
‘That you may be filled unto all the fullness of God.' God is ready to give of Himself as much as we will receive. Each Christian may receive of that fullness to the measure that He is willing and able to receive it, and all the members of His true church as a whole may receive it, for it is inexhaustible and beyond measure. And the more they are open to Him the more they will receive of His fullness until they are completely filled.
In Colossians 2:2 Paul expresses his similar longing that the hearts of God's people might be knitted together in love resulting in a full knowledge of Christ, in Whom are hid all the treasures of wisdom and knowledge. If we would fully know Christ we must first love, and as we love we will know more and more, and as we know more and more we will love more and more, and so it will go on. And this love is not what the world calls love. It is true, deep, spiritual love, like the love of God. And it results in revealing God-likensess to the world (Matthew 5:48).
The words for breadth, length, height and depth were all words used in contemporary literature to speak of cosmogonies and heavenly hierarchies, and Paul deliberately takes them over to express the wonder of God's love to and through His people. That love is beyond all, plumbing greater heights and depths than any supposed semi-divine beings could ever know or be.
‘Rooted and grounded.' Love, the love of God revealed in Christ, is the soil of the Christian, in which we are planted, His love that surrounds us and assists our growth unfolding that love in our hearts so that we begin to love as He loves. The language is of the soil and not of the building. There is no temple in mind here. (Note how he actually avoids saying ‘rooted and built up' as in Colossians 2:7). It connects with the significance of John's baptism as the product of the rain-drenched earth. The Spirit is poured down and the roots grow and flourish (Isaiah 44:2-5).
‘May be strong to apprehend.' In extra-Biblical literature the verb means ‘to acquire power, to prevail'. By His strengthening we are made strong to apprehend the full panoply of love, not only to appreciate it but also to firmly lay hold on it. When light came into the world mankind did not lay hold of it (John 1:1-18). But those who were His people did. They received it and laid hold of it right gladly. And now they must also apprehend with strength the love it revealed. They may bask in it but that is not all. They must also take it and make it their own, allowing it to posses them and flow through them. They are to be revelations of His love.
‘With all God's people (the saints).' It will take the whole of the people of God to apprehend the whole, for none are sufficient of themselves to reveal God's infinite love. We will need each other. Not one must be lacking. There is no room for inner circles here.
‘What is the breadth and length and height and depth.' Some would see in this the dimensions of the Temple of chapter Ephesians 2:20-22 in terms of Ezekiel's heavenly archetype. The idea being that it is depicting a Temple of the love of God which we may enter and enjoy in all its fullness as we recognise its huge dimensions, so that we can, by being united in it, grasp and know the wonder of the love of Christ, and as one Temple know and experience the fullness of His people and our part with them, the very fullness of God. But there has not been a hint of such a temple since he digressed in Ephesians 3:1 and this interpretation, true though it is, is laying too much stress on an uncertain connection. Paul could not go on as though he had not digressed and expect his readers to appreciate the fact. Had he wished them to do so he would somehow have indicated it. Rather it surely has in mind divine dimensions, the divine dimensions of love using language plundered from the mysteries to depict an even greater and all consuming mystery. God's love is as broad and long and wide and deep as anything in the whole creation and beyond.
‘And to know the love of Christ which passes knowledge.' Glorious contradiction. It is a love which passes knowledge and yet we can know it. Many a mother gives herself wholly for her children, but none even faintly to the extent to which He gives Himself for us. It is beyond our comprehension. But there is a play on the word ‘know' here. We can know it, we can know it fully in our experience, but without even beginning to comprehend its vastness which is beyond knowledge.
‘Filled unto all the fullness of God.' This is, of course, in the sphere of love. Our love as a whole will attain to His, and indeed will become like His, beyond all measure (John 17:21-23; John 17:26). Although the fullness of the experience of God's love in all its fullness can also only mean the fullness of blessing too.