Abraham is first and most important of the patriarchs. Today his historical existence is no seldom disputed.  However, we have so few historical facts that it isn’t possible to paint a coherent picture of him.  Because Genesis 14 places Abraham among the ranks of the Canaanite secondary kings, and older texts draw parallels to the statutes collected by  King Hammurabi (1728-1686 BC), it is believed that he lived around that time.  Others go even further and see him as having arrived in Canaan with a wave of nomads from the desert between 2000 and 1700 BC.  He is believed to originate either from Haran or from Ur in Chaldaea, the southern foothills of the Mesopotamian plains.  He comes from a polytheistic clan, sets out with a fairly small "extended family" and arrives in Canaan where he has to assert himself and settle in, sometimes aggressively, sometimes peacefully. The conditions that were contrived genealogically have him as a central figure in the tribe.  According to Genesis 25, Verses 7 to 11, Abraham died at the age of 175 “old and having had his fill of life” and was buried by his sons Isaaac and Ismael alongside Sarah in Mamre grove. 

Abraham is more than only a historically authenticated person. He is at the same time a typical example of God’s people.  In him Israel saw itself as reified according to God’s plan.  He  revered his God whom also his kin accepted.  Abraham is the type of the tolerant Jahwe worshipper who does not question God's plan. (departure to Egypt, return, "sacrifice" of Isaac).  He is also the doubting Israelite (infertility of his wife Sarah, exile, Babylonian captivity) and thus a central figure of  biblical belief, and many valuable traits are associated with him.  He is God’s friend (covenant), servant and important confidante, and therefore an unshakable symbol of belief... Because we are talking about Abraham’s belief at a time when the laws have not yet been established, Paul derives that belief is more important than laws.
 
Abraham appears separately in the catacomb painting of the second century and on the sarcophagi of the third century, full-bearded in girded skirt with the sacrificial knife in his hand, holding the hand of young Isaac or with him at his feet.  Whole series of representations are found in the mosaics from Santa Maria Maggiore in Rome (around 400 AD), in a manuscript from St. Gallen from the ninth century,  in the concordants of the fourteenth century etc.  See also Trinity icon (the meeting in Mamre with Abraham and Sarah).