principle which it was the great work of Paul's life to exemplify, that God's care and love and providence are over all His works, that His mercies are not restrained to any one nation, but that, having made of one all nations upon the face of the earth, His blessings are bestowed upon them all alike. This truth here taught by St. Paul has been slow to make its way. Men have been slow to acknowledge the equality of all nations in God's sight, very slow to give up their own claims to exceptional treatment and blessing on the part of the Almighty. The great principle enunciated by the Apostle struck, for instance, at the evil of slavery, yet how slowly it made its way. Till thirty years ago really good and pious men saw nothing inconsistent with Christianity in negro slavery. Christian communions even were established grounded on this fundamental principle, the righteous character of slavery. John Newton was a slave trader, and seems to have seen nothing wrong in it. George Whitfield owned slaves, and bequeathed them as part of his property to be held for his Orphan House in America. But it is not only slavery that this great principle overthrows. It strikes down every form of injustice and wrong. God has made all men of one; they are all equally His care, and therefore every act of injustice is a violation of the Divine law which is thus expressed. Such ideas must have seemed exceedingly strange, and even unnatural to men accustomed to reverence the teaching and study the writings of guides like Aristotle, whose dogma was that slavery was based on the very constitution of nature itself which formed some men to rule and others to be slaves. [169] That period of retirement at Tarsus may have been utilised by St. Paul in studying classical literature and Greek philosophy by way of preparation for that life's work among the Gentiles, to which he was appointed at his conversion. [170] There are frequent notices of the altars to the unknown gods in ancient Greek writers: as in Pausanias, _Description of Greece_, vol. i., p. 2 (Shilleto's translation); _Life of Apollonius_, by Philostratus, vi., 3; Lucian's _Philopatris_, 29. See, however, for exhaustive discussions of this point, and the whole subject of the topography of ancient Athens, Lewin's _St. Paul_, vol. i., p. 242; Farrar's _St. Paul_, ch. xxvii., and Conybeare and Howson's _St. Paul_, vol. i., ch. x. Spon and Wheeler were travellers of the seventeenth century, whose works on this subject are important as showing Athens as it existed before modern changes. Some of the reports of travels in Greece, made by eminent scholars in the same century, and now very little known, may be found in the early volumes of the Philosophical Transactions of the Royal Society.