#she said to Abraham

"Sarah said to Abraham"

#Drive out

"send away" or "get rid of" (UDB)

#this slave woman and her son

This refers to Hagar and Ishmael. Sarah probably did not refer to them by name because she was angry with them.

#with my son, with Isaac

"with my son Isaac"

#This thing was very grievous to Abraham

"Abraham was very unhappy about what Sarah said"

#because of his son

"because it was about his son." It is implied that this means his son, Ishmael. (See: [[:en:ta:vol1:translate:figs_explicit]])