Verses 15, 16

Each member acts in its place; each part has its place. This place may be a hidden one, but it is not the less important; the thought presented is that of the growth of the body. A soul which is lively builds up others; the Spirit acts in souls which turn not back; the Gospel working produces inward blessing. We see, as we have said, in the place where all fullness dwells all becomes grace, even trials; because they make us enjoy with intelligence the counsels of God. If any evil occurs, it becomes only the opportunity for manifesting the love of Jesus, and this serves to strengthen faith.
But all consists in our growing up into the Head; this is the only true growth which is in the knowledge of Jesus; because this knowledge is that of grace. The Spirit acts by the word (through faith and understanding of the things of God), all the while it is my life which grows and communicates to me a developed manifestation of life.
But let us go back to what we have a right to expect from the children of God; I am here speaking of the oneness of faith and of the knowledge of Christ. If love dwells in us and we think of the members of Christ; that will lead us to ask that they may grow according to the measure of the stature of the fullness of Christ. But alas! many are often more occupied with this present life than seeking the growth of souls. Love is of God, and it is always powerful. If we were in a healthy state, we should grow in God. Faithfulness in the walk is necessary, if we would not grieve the Spirit; there must be the hidden life, that is to say, the heart must abide in Jesus; in a word, Christ should be the end of all our life. There is enough love in Jesus to make His members grow.
If we had sufficient love, we should draw out of Jesus what would produce this growth in others; and we need it in the present time when there are so many things that dim the testimony of the saints. Our part really is to be separate from evil; we must see Christ so clearly as to be able to say: This or that is not of Christ; and if persons are overwhelmed by cares, it is impossible that Christ should be discerned by them so as to deliver them from things which are like Christ, but which still are not Himself. What we have to seek after is to be sufficiently spiritual as to be able to realize what Christ is; the effect of this will be subjects of intercession, which will doubtless cause sorrow of heart, because the faults and failures of the members of the body are borne there; but nevertheless, where love is in action, there will be always joy.
Verse 17.
There is a principle here, which it is of importance to have a firm hold of, it is-that the whole conduct of the Christian flows from salvation, and is not in order that he may be saved; it is not that we do not gain something, or that Paul does not exhort us to run towards the mark (1 Cor. 9:24); but the whole walk of the Christian ought to be the manifestation of a new life. The moment that we hear an exhortation as to conduct, and that we do not hear it as addressed to a saved person, the Gospel is displaced. All must be addressed to me, as a child of God; this is why the apostle says, "I beseech you," etc.; it is because of this grace that I beseech you. The moment that I mix up an exhortation with the freeness of salvation, man is not in the position in which Christ has set him; it may have the appearance of piety, but the fact remains, that if I exhort and at the same time admit a question about salvation, I deny, and I have not a right consciousness of, the state of ruin in which man is, any more than of salvation.