"Yahweh helped Sarah"
"gave birth to Abraham's son"
"when Abraham was very old"
"at the exact time that God had told him it would happen"
"Abraham named his newborn son, the one Sarah gave birth to, Isaac" or "Abraham named their newborn son Isaac"
"When his son Isaac was eight days old, Abraham circumcised him"
"God has caused me to laugh joyfully"
"everyone who hears about what God has done for me"
"No one would have ever said to Abraham that Sarah will nurse children"
"feed a baby her own milk"
"Isaac grew, and when he no longer needed his mother's milk, Abraham had a large feast"
"Ishmael, the son of Hagar the Egyptian and Abraham"
"laughing at Isaac"
"Sarah said to Abraham"
"send away" or "get rid of"
This refers to Hagar and Ishmael. Sarah probably did not refer to them by name because she was angry with them.
"Abraham was very unhappy about what Sarah said"
"because it was about his son." It is implied that this means his son, Ishmael.
"Do everything that Sarah says to you about them"
"Isaac is the one who will be the forefather of the descendants I promised to give you"
These words could refer to 1) food in general or 2) bread specifically.
"a bag of water." The water container was made out of animal skin.
This refers to the distance that a person could shoot an arrow with a bow. This is about 100 meters.
"I do not want to watch the boy die"
"she cried out loudly and wept" or "she wept loudly"
"the sound of Ishmael"
"a messenger from God" or "God's messenger"
Here "heaven" means the place where God lives.
"What is wrong" or "Why are you crying"
"help the young man stand up"
"I will make his descendants become a great nation" or "I will make him become the ancestor of a great nation"
"God caused Hagar to see" or "God showed her"
"the container made of skin" or "the bag"
"the boy" or "Ishmael"
"God guided the young man" or "God blessed the young man"
"became very skilled at using a bow and arrows"
This phrase marks the beginning of a new part of the story. If your language has a way for doing this, you could consider using it here.
This is the name of a man.
"commander of his army"
The word "his" refers to Abimelech.
"God blesses everything you do"
"promise me with God as your witness"
"that you will not lie to me"
"will deal honestly with me and my descendants"
"Be as faithful to me and to the people of the land as I have been to you"
"I swear to be as faithful to you and your people as you have been to me"
Possible meanings are 1) Abraham was complaining about what happened or 2) "Abraham also rebuked Abimelek"
"because Abimelek's servants had taken one of Abraham's wells"
"This is the first time I have heard about it"
This is a sign of friendship and that Abraham agrees to make covenant with Abimelek
"you will take"
"from me"
The word "it" refers to the gift of seven lambs.
"to prove to everyone"
Translators may add a footnote saying "Beersheba can mean either "well of the oath" or "well of seven."
"Abraham and Abimelech"
This is an evergreen tree that can grow in the desert. It can be stated more generally. Alternate translation: "a tree"
"the God who lives forever"
"for a long time"