Matthew Henry writes on Ephesiasns 3:14-21
We now come to the second part of this chapter, which contains Paul's devout and affectionate prayer to God for his beloved Ephesians. - For this cause. This may be referred either to the immediately foregoing verse, That you faint not, etc., or, rather, the apostle is here resuming what he began at the first verse, from which he digressed in those which are interposed. Observe,
... III. What the apostle asks of God for these his friends - spiritual blessings, which are the best blessings, and the most earnestly to be sought and prayed for by every one of us, both for ourselves and for our friends.
1. Spiritual strength for the work and duty to which they were called, and in which they were employed: That he would grant you, according to the riches of his grace, to be strengthened, etc. The inner man is the heart or soul. To be strengthened with might is to be mightily strengthened, much more than they were at present; to be endued with a high degree of grace, and spiritual abilities for discharging duty, resisting temptations, enduring persecutions, etc. And the apostle prays that this may be according to the riches of his glory, or according to his glorious riches - answerable to that great abundance of grace, mercy, and power, which resides in God, and is his glory: and this by his Spirit, who is the immediate worker of grace in the souls of God's people.
Observe from these things, That strength from the Spirit of God in the inner man is the best and most desirable strength, strength in the soul, the strength of faith and other graces, strength to serve God and to do our duty, and to persevere in our Christian course with vigour and with cheerfulness. And let us further observe that as the work of grace is first begun so it is continued and carried on, by the blessed Spirit of God.
2. The indwelling of Christ in their hearts, Eph 3:17. Christ is said to dwell in his people, as he is always present with them by his gracious influences and operations.
Observe, It is a desirable thing to have Christ dwell in our hearts; and if the law of Christ be written there, and the love of Christ be shed abroad there, then Christ dwells there. Christ is an inhabitant in the soul of every good Christian. Where his spirit dwells, there he swells; and he dwells in the heart by faith, by means of the continual exercise of faith upon him. Faith opens the door of the soul, to receive Christ; faith admits him, and submits to him. By faith we are united to Christ, and have an interest in him.
3. The fixing of pious and devout affections in the soul: That you being rooted and grounded in love, stedfastly fixed in your love to God, the Father of our Lord Jesus Christ, and to all the saints, the beloved of our Lord Jesus Christ. Many have some love to God and to his servants, but it is a flash, like the crackling of throns under a pot, it makes a great noise, but is gone presently. We should earnestly desire that good affections may be fixed in us, that we may be rooted and grounded in love. Some understand it of their being settled and established in the sense of God's love to them, which would inspire them with greater ardours of holy love to him, and to one another. And how very desirable is it to have a settled fixed sense of the love of God and Christ to our souls, so as to be able to say with the apostle at all times, He has loved me! Now the best way to attain this is to be careful that we maintain a constant love to God in our souls; this will be the evidence of the love of God to us. We love him, because he first loved us. In order to this he prays
4. For their experimental acquaintance with the love of Jesus Christ. The more intimate acquaintance we have with Christ's love to us, the more our love will be drawn out to him, and to those who are his, for his sake: That you may be able to comprehend with all saints, etc. (Eph 3:18, 19); that is, more clearly to understand, and firmly to believe, the wonderful love of Christ to his, which the saints do understand and believe in some measure, and shall understand more hereafter. Christians should not aim to comprehend above all saints; but be content that God deals with them as he uses to do with those who love and fear his name: we should desire to comprehend with all saints, to have so much knowledge as the saints are allowed to have in this world. We should be ambitious of coming up with the first three; but not of going beyond what is the measure of the stature of other saints. It is observable how magnificently the apostle speaks of the love of Christ. The dimensions of redeeming love are admirable: The breadth, and length, and depth, and height. By enumerating these dimensions, the apostle designs to signify the exceeding greatness of the love of Christ, the unsearchable riches of his love, which is higher than heaven, deeper than hell, longer than the earth, and broader than the sea, Job 11:8, 9. Some describe the particulars thus: By the breadth of it we may understand the extent of it to all ages, nations, and ranks of men; by the length of it, its continuance from everlasting to everlasting; by the depth of it, its stooping to the lowest condition, with a design to relieve and save those who have sunk into the depths of sin and misery; by its height, its entitling and raising us up to the heavenly happiness and glory. We should desire to comprehend this love: it is the character of all the saints that they do so; for they all have a complacency and a confidence in the love of Christ: And to know the love of Christ which passeth knowledge, Eph 3:19. If it passeth knowledge, how can we know it? We must pray and endeavour to know something, and should still covet and strive to know more and more of it, though, after the best endeavours, none can fully comprehend it: in its full extent it surpasses knowledge. Though the love of Christ may be better perceived and known by Christians than it generally is, yet it cannot be fully understood on this side heaven.
5. He prays that they may be filled with all the fulness of God. It is a high expression: we should not dare to use it if we did not find it in the scriptures. It is like those other expressions, of being partakers of a divine nature, and of being perfect as our Father in heaven is perfect. We are not to understand it of his fulness as God in himself, but of his fulness as a God in covenant with us, as a God to his people: such a fulness as God is ready to bestow, who is willing to fill them all to the utmost of their capacity, and that with all those gifts and graces which he sees they need. Those who receive grace for grace from Christ's fulness may be said to be filled with the fulness of God, according to their capacity, all which is in order to their arriving at the highest degree of the knowledge and enjoyment of God, and an entire conformity to him.
The apostle closes the chapter with a doxology, Eph 3:20, 21. It is proper to conclude our prayers with praises. Our blessed Saviour has taught us to do so. Take notice how he describes God, and how he ascribes glory to him. He describes him as a God that is able to do exceedingly abundantly above all that we ask or think. There is an inexhaustible fulness of grace and mercy in God, which the prayers of all the saints can never draw dry. Whatever we may ask, or think to ask, still God is still able to do more, abundantly more, exceedingly abundantly more. Open thy mouth ever so wide, still he hath wherewithal to fill it. Note, In our applications to God we should encourage our faith by a consideration of his all-sufficiency and almighty power. According to the power which worketh in us. As if he had said, We have already had a proof of this power of God, in what he hath wrought in us and done for us, having quickened us by his grace, and converted us to himself. The power that still worketh for the saints is according to that power that hath wrought in them. Wherever God gives of his fulness he gives to experience his power. Having thus described God, he ascribes glory to him. When we come to ask for grace from God, we ought to give glory to God. Unto him be glory in the church by Christ Jesus. In ascribing glory to God, we ascribe all excellences and perfections to him, glory being the effulgency and result of them all. Observe, The seat of God's praises is in the church. That little rent of praise which God receives from this world is from the church, a sacred society constituted for the glory of God, every particular member of which, both Jew and Gentile, concurs in this work of praising God. The Mediator of these praises is Jesus Christ. All God's gifts come from his to us through the hand of Christ; and all our praises pass from us to him through the same hand. And God should and will be praised thus throughout all ages, world without end; for he will ever have a church to praise him, and he will ever have his tribute of praise from his church. Amen. So be it; and so it will certainly be.