Abram overshot his destination and eventually ended up in Egypt. (Venturing into Egypt had eternal consequences for Abram and the whole world. Hagar was from Egypt and gave birth to Ishmael and we know where (!) his descendants have taken the whole world to). Probably, Abram was not sure of the extent of the land that God promised him. He had started out believing God’s word not knowing where he was going.

When he arrived in Canaan, he saw that the Canaanites had occupied the land and so might have thought that was not the destination. There is a hint in the book of Hebrews in the Bible about this: “and he went out, not knowing whither he went” – Heb 11:8. Before entering Egypt, he requested his wife Sarai to tell the Egyptians that she was his sister. (Sarai was also the biological sister of Abram and was a beautiful woman). Abram was a new believer and his faith in God was at a very early stage. Abram was afraid that he might be killed by the Egyptians if they came to know that he was her husband.

The Serpent was trying to capitalize on the situation. He provoked the Egyptian Pharaoh to bring Sarai so that he could marry her. Satan would use Pharaoh to bring about his seed and thus nullify the possibility of Sarai bringing forth the Seed of the woman. However, God can never be tricked by the vile acts of His enemy. The Lord plagued Pharaoh and his house with great plagues because of Sarai Abram's wife. – Gen 12:11. Pharaoh commanded his men to send Abram away with his wife and all that he had.
Abram returned to Canaan and dwelt there – the Promised Land.