After the deluge Noe and his family settled once more upon the land, and for a time their descendants remained faithful to God; but later they became wicked and undertook to build a great tower (Gen. 11), which they thought would reach up to Heaven. They believed, perhaps, that if ever there should be another deluge upon the earth, they could take refuge in the tower. But God was displeased with their conduct and prevented them from completing the tower by confusing their tongues or language so that they could not understand one another. Then those who spoke the same language went to live in the same part of the country, and thus the human race was scattered over the earth, and the different nations had different languages.
After a time they were all losing the knowledge of the true God and beginning to worship idols. God did not wish that the whole human race should forget Him, so He selected Abraham to be the father and head of one chosen people who should always worship the true God. He sent Abraham from his own country into another, and promised him great things, and renewed to him the promises of the Redeemer first made to Adam and Eve. After the death of Abraham, God raised up, from time to time, prophets to tell the people His holy will, to warn them of their sins and the punishment they would receive, and to remind them of the promised Messias. Prophets are men that God inspires to tell the future. They tell what will happen often hundreds of years after their own death. They do not guess at these things, but tell them with certainty. At times, statesmen can foresee that there will be a war in a country at a certain time; but they are not prophets, because they only guess at such things, or know them by natural signs; and very often things thus foretold do not occur. True prophecy is the foretelling of something which could not be known by any means but inspiration from God.
Neither are persons who call themselves fortune-tellers prophets, but only sinful people, who for money tell lies or guess at the future. It is a great sin to go to them or listen to them, as we shall see later in another question.
At the time promised, God sent His Son—Our Lord—to redeem the world and save all men. He came to save all men, and yet He remained upon earth only thirty-three years. We can easily understand that by His death He could save all those who lived before He did; but how were they to be saved who should live after Him, down to the end of the world? How was His grace to be given to them? How were they to know of Him, or of what He taught? All this was to be accomplished by His Church.