Hebrews 11:8

‘By faith Abraham, when he was called, obeyed to go out to a place which he was to receive for an inheritance, and he went out, not knowing where he went.'

Noah's faith pointed to judgment on the world, and preserved alive a remnant to go into the future. But now arose one who would offer hope to the whole world (Genesis 12:3). Abraham also believed God, and believed that He would reward his faith. And his faith was counted for righteousness (Genesis 15:6). For when he was called by God to go to a strange and unknown country, simply on the basis that he was promised that he would receive it as an inheritance, he went, not knowing where he was going. Because he believed God, he trusted Him implicitly and was fully obedient. He too was a man of faith in God.

It is quite probable that his faith had been built up by studying the tablets which were in his father's house, which contained information about his family's past, much as we find them today in the first eleven Chapter s of the book of Genesis. For someone kept them faithfully in order that they might be used by Moses in his great work at the birth of the nation of Israel. But it also resulted from his direct encounters with God, some of which are described for us in Genesis.