One of the many reasons we can trust the Bible is because of the way the Bible treats its heroes. Instead of whitewashing their mistakes and portraying them as saints, the Bible tells their entire stories, defects and all. And that's certainly true for Abraham.

Even though Abraham is called the friend of God, even though he's the father of the Jewish nation, even though he's included in the New Testament as the supreme example of faith, he had some tremendous character deficiencies and made some tremendous mistakes in his life. That ought to be an encouragement to us because if God can use Abraham, God can use anybody!
Walking by Faith, A Study of the Life Of Abraham- Robert Jeffress

Dr. Robert Jeffress is senior pastor of the sixteen-thousand member First Baptist Church, Dallas, Texas, and a Fox News contributor. His daily radio program, Pathway to Victory, is heard on more than one thousand stations nationwide, and his weekly television program is seen in 195 countries around the world.
Known for his bold, biblical teaching, Jeffress has made more than four thousand guest appearances on various radio and television programs, such as Fox l Friends, Hannity, Varney & Co., and Real Time with Bill Maher. He is the author of nearly thirty books, including Not All Roads Lead to Heaven, A Place Called Heaven, Choosing the Extraordinary Life, Courageous, Invincible,
18 Minutes with Jesus, and What Every Christian Should Know.