Before he was called by God, Abraham was polytheistic, which meant that he believed in many gods.
Before his call, Abram (as he was originally known) and his wife Sarai (who later became known as Sarah) were old and childless. Abraham was 75 when he left his home and he became the first to teach the idea of one God (monotheism). As a result of his response to God, he became ‘Abraham’ which means ‘Father of the people’.
God promised Abraham that he would become the father of a great nation. This is known as the Abrahamic covenant (the promise God made to Abraham).
God’s promise to Abraham is recorded in Genesis:
I will make you a great nation and I will bless you; I will make your name great and you will be a blessing. I will bless those who bless you, and those who curse you I will curse, and in you all the families of the earth will be blessed.Genesis 12:1-3
Following this, at the age of 75, Abraham and his wife made the journey to Canaan (modern day Palestine, Syria and Israel). Here God blessed them with a child.
Moses was called by God to help the Israelites (who were Jewish) escape from Egypt. This is remembered in the Jewish faith today as the Passover.
The Jews were helped on their journey by God - the same God who had promised Abraham that He would look after the Jewish people. God parted the Red Sea to help them escape.
When they reached Mount Sinai, in present day Egypt, God spoke to Moses high on the mountain slopes. God made a deal (called a covenant) with the Jews that renewed the one He had made with Abraham.
You have seen what I did to the Egyptians and how I bore you on eagles' wings and brought you to myself. Now, therefore, if you obey my voice and keep my covenant you shall be my treasured possession of all the peoples.Exodus 19:4-5
As part of this covenant, the Jews received some rules from God in order to live as His people. These are known as the Ten Commandments.