That Christ may dwell in your hearts by faith. Reversing the usual order, the prayer begins (Ephesians 3:16) by asking the blessing of the Third Person of the Godhead; now we have a cluster of petitions connected with the Second Person.
The first of these is for the indwelling of Christ in their hearts, as opposed to mere occasional visits or influences from Christ; the instrument by which this blessing is attained being their faith.
Christ exercising a constant power within them, both in the active and passive movements of the heart, giving the sense of pardon and acceptance, molding the will, sweetening the emotions, enlightening and confirming the conscience, purifying the whole springs and principles of action.
This to be secured by their faith, opening the door, receiving Christ in all his fullness, resting and living on him, believing his promises, and longing for his appearing the second time. In order that ye, having been rooted and grounded in love.
Two images are combined to make the idea emphatic—that of a tree and that of a building; denoting what is both the starting-point and the support of the Christian's life, viz. love. In what sense? The love of Christ is specified afterwards (Ephesians 3:19), but this may be as a pre-eminent branch of that manifold love which bears on the Christian life—the love of the Father, Son, and Holy Ghost; the love of the brethren to one another; and the reciprocal love evoked from the believer by the reception of this love.
Evidently it is implied that the Christian life can begin and flourish only in such an atmosphere of love; as warm sunshine is needed to start and advance the life of a plant, so love is needed to start and carry on the life of the soul.
Experience of Divine love is a great quickening and propelling power. "One glance of God, a touch of his love, will free and enlarge the heart, so that it can deny all and part with all and make an entire renunciation of all to follow him" (Archbishop Leighton).