We shall see that in his later years Dr.Livingstone saw reason to modify some of these opinions; surveying the Evangelical Churches from the heart of Africa, he came to think that, established or non-established, they did not differ so very much from each other, and that there was much good and considerable evil in them all.
In his application to the London Missionary Society, Livingstone stated his ideas of missionary work in comprehensive terms: "The missionary's object is to endeavor by every means in his power to make known the gospel by preaching, exhortation, conversation, instruction of the young; improving, so far as in his power, the temporal condition of those among whom he labors, by introducing the arts and sciences of civilization, and doing everything to commend Christianity to their hearts and consciences.

He will be exposed to great trials of his faith and patience from the indifference, distrust, and even direct opposition and scorn of those for whose good he is laboring; he may be tempted to despondency from the little apparent fruit of his exertions, and exposed to all the contaminating influence of heathenism." He was not about to undertake this work without counting the cost.

"The hardships and dangers of missionary life, so far as I have had the means of ascertaining their nature and extent, have been the subject of serious reflection, and in dependence on the promised assistance of the Holy Spirit, I have no hesitation in saying that I would willingly submit to them, considering my constitution capable of enduring any ordinary share of hardship or fatigue." On one point he was able to give the Directors very explicit information: he was not married, nor under any engagement of marriage, nor had he ever made proposals of marriage, nor indeed been in love! He would prefer to go out unmarried, that he might, like the great apostle, be without family cares, and give himself entirely to the work.
His application to the London Missionary Society was provisionally accepted, and in September, 1838, he was summoned to London to meet the Directors.

A young Englishman came to London on the same errand at the same time, and a friendship naturally arose between the two.
Livingstone's young friend was the Rev.Joseph Moore, afterwards missionary at Tahiti; now of Congleton, in Cheshire.

Nine years later, Livingstone, writing to Mr.Moore from Africa, said: "Of all those I have met since we parted, I have seen no one I can compare to you for sincere, hearty friendship." Livingstone's family used to speak of them as Jonathan and David.