Then God promised to look after Abraham, and Abraham agreed to follow him. God told Abraham that his mob had to do a young man operation on all their boys, to show that they agreed with God. After that, Abraham had a son called Isaac, and 8 days later Abraham did a young man operation on him. After that, Isaac grew up and had a son called Jacob, and he did that operation on him too. And Jacob did the same for his 12 sons, and those 12 men became our grand-fathers that lived a long time ago.