During his stay in Egypt, Abraham gave evidence that he was not free from human weakness and imperfection. In concealing the fact that Sarah was his wife, he betrayed a distrust of the divine care, a lack of that lofty faith and courage so often and nobly exemplified in his life. Sarah was fair to look upon, and he doubted not that the dusky Egyptians would covet the beautiful stranger, and that in order to secure her, they would not scruple to slay her husband. He reasoned that he was not guilty of falsehood in representing Sarah as his sister, for she was the daughter of his father, though not of his mother. But this concealment of the real relation between them was deception. No deviation from strict integrity can meet God's approval. Through Abraham's lack of faith, Sarah was placed in great peril. The king of Egypt, being informed of her beauty, caused her to be taken to his palace, intending to make her his wife. But the Lord, in His great mercy, protected Sarah by sending judgments upon the royal household. By this means the monarch learned the truth in the matter, and, indignant at the deception practiced upon him, he reproved Abraham and restored to him his wife, saying, "What is this that thou hast done unto me? . . . Why saidst thou, She is my sister? So I might have taken her to me to wife. Now therefore behold thy wife, take her, and go thy way."

Under sit ophold i Ægypten viste Abraham, at han ikke var fri for menneskelig svaghed og ufuldkommenhed. Ved at skjule, at Sara var hans hustru, viste han, at han ikke stolede på Guds omsorg. Han viste mangel på den ophøjede tro og det mod, som hans liv ellers frembød så mange smukke eksempler på. Sara var smuk, og han var ikke i tvivl om, at de mørklødede ægyptere ville begære den smukke udlænding, og at de ikke ville betænke sig på at slå hendes mand ihjel for at få fat på hende. Han ræsonnerede, at han ikke gjorde sig skyld i nogen usandhed ved at sige, at Sara var hans søster, for hun var hans faders datter, blot ikke hans moders. Men denne fortielse af det virkelige forhold mellem dem var et bedrageri. Gud billiger ingen afvigelse fra fuldkommen ærlighed. Ved Abrahams mangel på tro blev Sara bragt i stor fare. Da kongen af Ægypten hørte om hendes store skønhed, lod han Hende bringe til slottet for at gøre hende til sin hustru. Men i sin store nåde beskyttede Herren Sara ved at lade straffedomme komme over kongens hus. Derved fik kongen sandheden at vide, og harmfuld over, at han var blevet bedraget, bebrejdede han Abraham og sendte hans hustru tilbage med ordene: "Hvad har du gjort imod mig! ..... Hvorfor sagde du, at hun var din søster, så at jeg tog hende til hustru? Se, her har du nu din hustru, tag hende og gå bort!"