May I say a word here about the grounds on which this obligation to witness rests for us? If Jesus Christ had never said, 'Go ye into all the world and preach the Gospel to every creature,' it would not have made a bit of difference as to the imperative duty that is laid upon all Christian men; for that arises, not from that command, which only gives voice to a previous obligation, but it flows, from the very nature of things, from the message that we receive from our links with other men and from the constitution and make of our own natures.
It flows directly from the gift that we have received. There are plenty of truths which, _per se_, carry with them no obligation to impart them. But any truth in which is wrapped up the possible happiness of another man, any truth which bears upon moral or spiritual subjects, carries with it the strongest obligation to impart it. We have such large insights into God and His love as the Gospel gives us, not that we may eat our morsel alone, or merely sun ourselves in the light, and expatiate in the warmth of the beams that come to us, but that we may share them with all around: 'God, who commanded the light to shine out of darkness hath shined into our hearts,' that we may 'give the light of the knowledge of the glory of God in the face of Jesus Christ.'
The obligation arises from the links that knit us all together. 'Am I my brother's keeper?' Why, the question answers itself. If he is _your_ 'brother,' you are certainly _his_ 'keeper.' And you cannot shuffle off the obligation by any irrelevant pitting of one field of Christian work against another; still less by any criticism, hostile or friendly, as it may be, of the methods of Christian work, or of the parity and elevation of the character and motives of the workers. Humanity is one, linked by a mystic chain, and every link of it should thrill by a common impulse; and through all the members there should circulate a common life. That great thought is one of the gains that the Gospel has brought us, and in the presence of it and our indebtedness and obligation to every man, woman, and child that bears the form of man, all geographical limits to Christian witnessing seem supremely absurd and incongruous. You cannot get rid of your obligation by saying, 'I do not care about foreign missions, I go in for home ones.' And you cannot get rid of it by chiming in an ignorant second to the talk that has been going on lately, carping at or criticising methods of work. It would be a very strange thing if we had hit all at once, in the very beginning of an enterprise, upon the best of all possible methods; and it would be a very strange thing if the mission-field is the only one where there are no lazy workers and selfish motives and unworthy occupants of high places. All that is true about home as it is about other places. But grant it all, and back comes the obligation based upon the nature of the truth that we have received, upon our links with our brethren, and upon our loyalty to our Master, and it peals into the ears of every Christian man and woman: 'Thou art a witness of these things'; and 'to this end wert thou born again, that thou mightest bear witness to the truth.'
Ah, brethren! the issues of faithfulness to that high function are sweet and blessed and wonderful. A witnessing Christian will be a believing Christian; for there is no surer way to deepen my own convictions about any moral or spiritual truth than to constitute myself their humble servant to proclaim them. Whosoever is a believer should be an apostle, and if he is an apostle he will be tenfold a believer. There is nothing which will give a man a firmer grasp of the Gospel for his own soul than when he finds that, ministered by his humble efforts, it produces in other hearts the same effects which he finds it working upon himself. There is no page in the great book of the evidences of the truth of Christianity more conclusive than that which in the last century has been written by the experience of Christian missions. Let the objectors, Jannes and Jambres, who withstood Moses, let them do the same with their enchantments, and then we will discuss the questions of the truth of the Gospel with them.