1. _This spiritual strengthening is achieved by the indwelling Christ welcomed and retained in the heart by faith._--"That Christ may dwell in your hearts by faith" (ver. 17). The source of this strength is not in us; we cannot evoke it by any voluntary effort of our own. It is a Divine power working in us (ver. 20). It is the Christ within us making Himself felt in our otherwise enfeebled powers. We are invested with the strength of Christ by our faith in Christ; and increase of strength comes with increase of faith. The faith that receives Christ into the heart must be constantly exercised to keep Him there, and to derive inspiration and help from Him in attaining spiritual growth and in doing useful work. 2. _This spiritual strengthening is cherished by an accession of Christian love._--"That ye, being rooted and grounded in love" (ver. 17). The double metaphor gives emphasis to the idea--"rooted," a tree; "grounded" a building. When Christ is planted and settled in our hearts, love is shed abroad there, and becomes the genial soil in which our graces grow, and the basis of all our thought and action. Love is strength, the most reliable, sustaining, and victorious kind of strength. +II. For a clearer comprehension of the immeasurable love of Christ+ (vers. 18, 19).--Here the prayer rises in sublimity and comprehensiveness. The apostle prays that we may know the unknowable--"know the love of Christ, which passeth knowledge." There is nothing so fascinating as the love of Christ, ever leading us on by fresh revelations, and ever leaving the impression that there are unfathomable depths and inaccessible heights yet to be discovered. "Oh that Christ would," exclaimed the saintly Rutherford, "arrest and comprise my love and my heart for all. I am a bankrupt who have no more free goods in the world for Christ, save that it is both the whole heritage I have, and all my moveables besides. Lord, give the thirsty man a drink. Oh to be over ears in the well! Oh to be swimming over head and ears in Christ's love! I would not have Christ's love entering in me, but I would enter into it, and be swallowed up of that love. But I see not myself here, for I fear I make more of His love than of Himself, whereas He Himself is far beyond and much better than His love. Oh, if I had my sinful arms filled with that lovely one Christ! Blessed be my rich Lord Jesus, who sendeth not away beggars from His house with an empty dish. He filleth the vessel of such as will come and seek. We might beg ourselves rich, if we were wise, if we would but hold out our withered hands to Christ, and learn to seek, ask, and knock." The highest conceptions of the love of Christ are realised by the soul that prays.