And Sarai said unto Abram, Behold now, the LORD hath restrained me from bearing: I pray thee, go in unto my maid; it may be that I may obtain children by her. And Abram hearkened to the voice of Sarai. Genesis 16:2

As we saw in the last chapter, God reaffirmed his promise to Abraham that he would get his promised Son of Isaac. However as the years went on, him and Sarah again were losing faith. Sarah at the point figured she would never have children and told Abraham to mate with her servant Hagar

This event would have permanent consequences , not only just for Abraham and Sarah, but also the entire world

And he went in unto Hagar, and she conceived: and when she saw that she had conceived, her mistress was despised in her eyes. Genesis 16:4

Even though Sarah was the one who suggested Abraham take Hagar for another wife, when she conceived a child from Abraham it enraged her. And she despised and hated Hagar for this. This is a classic example in the Bible, where polygamy is always a disaster for those involved. Even though there were those in the Old Testament who practiced polygamy , it was never ordained by God. As God said in the beginning marriage was One Man and One Woman (Genesis 2:24)

And Hagar bare Abram a son: and Abram called his son’s name, which Hagar bare, Ishmael. Genesis 16:5

Muslims are descendants of Ishmael. So as you can see this child conceived out of the covenant of Marriage will cause major issues in the future for Israel. As God prophesied , Ishmael will be a wild man against everyone and hostile towards his brothers (Genesis 16:12)

So due to Abraham and Sarah’s lack of faith in Gods promise, they created a lot of new problems for them and the entire world.

And he saith unto them, Why are ye fearful, O ye of little faith? Then he arose, and rebuked the winds and the sea; and there was a great calm. Matthew 8:26