"Ye turned unto God from idols, to serve a living and true God." We cannot over-estimate the greatness of this change. Until we understand the unity of God, we can have no true idea of His character, and therefore no true idea of our own relation to Him. It was the plurality of deities, as much as anything, which made heathenism morally worthless. Where there is a multitude of gods, the real power in the world, the final reality, is not found in any of them; but in a fate of some sort which lies behind them all. There can be no moral relation of man to this blank necessity; nor, while it exists, any stable relation of man to his so-called gods. No Greek or Roman could take in the idea of "serving" a God. The attendants or priests in a temple were in an official sense the deity's ministers; but the thought which is expressed in this passage, of serving a living and true God by a life of obedience to His will, a thought which is so natural and inevitable to either a Jew or a Christian, that without it we could not so much as conceive religion--that thought was quite beyond a pagan's comprehension. There was no room for it in his religion; his conception of the gods did not admit of it. If life was to be a moral service rendered to God, it must be to a God quite different from any to whom he was introduced by his ancestral worship. That is the final condemnation of heathenism; the final proof of its falsehood as a religion. There is something as deep and strong as it is simple in the words, to serve the living and true God. Philosophers have defined God as the _ens realissimum_, the most real of beings, the absolute reality; and it is this, with the added idea of personality, that is conveyed by the description "living and true." But does God sustain this character in the minds even of those who habitually worship Him? Is it not the case that the things which are nearest to our hand seem to be possessed of most life and reality, while God is by comparison very unreal, a remote inference from something which is immediately certain? If that is so, it will be very difficult for us to serve Him. The law of our life will not be found in His will, but in our own desires, or in the customs of our society; our motive will not be His praise, but some end which is fully attained apart from Him. "My meat," said Jesus, "is to do the will of Him that sent Me, and to finish His work"; and He could say so because God who sent Him was to Him the living and true God, the first and last and sole reality, whose will embraced and covered all His life. Do we think of God so? Are the existence of God and the claim of God upon our obedience the permanent element in our minds, the unchanging background of all our thoughts and purposes? This is the fundamental thing in a truly religious life.