But "brethren" means more than this. It points not merely to Christian love, but to the common possession of a new life. If we are brethren, it is because we have one Father, because in us all there is one life. The name is often regarded as sentimental and metaphorical. The obligation of mutual love is supposed to be the main idea in it, and there is a melancholy hollowness and unreality in the very sound of it as applied to the usual average Christians of to-day. But the name leads straight to the doctrine of regeneration, and proclaims that all Christians are born again through their faith in Jesus Christ, and thereby partake of a common new life, which makes all its possessors children of the Highest, and therefore brethren one of another. If regarded as an expression of the affection of Christians for one another, "brethren" is an exaggeration, ludicrous or tragic, as we view it; but if we regard it as the expression of the real bond which gathers all believers into one family, it declares the deepest mystery and mightiest privilege of the gospel that "to as many as received Him, to them gave He power to become the Sons of God." They are "in Christ." These two words may apply to all the designations or to the last only. They are saints in Him, believers in Him, brethren in Him. That mystical but most real union of Christians with their Lord is never far away from the Apostle's thoughts, and in the twin Epistle to the Ephesians is the very burden of the whole. A shallower Christianity tries to weaken that great phrase to something more intelligible to the unspiritual temper and the poverty-stricken experience proper to it; but no justice can be done to Paul's teaching unless it be taken in all its depth as expressive of that same mutual indwelling and interlacing of spirit with spirit which is so prominent in the writings of the Apostle John. _There_ is one point of contact between the Pauline and the Johannean conceptions, on the differences between which so much exaggeration has been expended: to both the inmost essence of the Christian life is union to Christ, and abiding in Him. If we are Christians, we are in Him, in yet profounder sense than creation lives and moves and has its being in God. We are in Him as the earth with all its living things is in the atmosphere, as the branch is in the vine, as the members are in the body. We are in Him as inhabitants in a house, as hearts that love in hearts that love, as parts in the whole. If we are Christians, He is in us, as life in every vein, as the fruit-producing sap and energy of the vine is in every branch, as the air in every lung, as the sunlight in every planet.