The 21st chapter of Genesis records three seemingly separate events recorded for us:
•1-14 The birth of Isaac
•15-21 The provision of Ishmael and Hagar
•22-34 The payment for a well in the land of promise
There is a common thread but it deals not with the persons involved or the event but rather the God who keeps His promises:
•In chapter 18 God promised Sarah and Abraham that they would have a son.
•In chapter 16 God promised that Ishmael would live to become a mighty nation.
•In chapter 13 God promised Abraham that the land that they were living in was to be his and his descendants after him.
In the 21st chapter all three of these promises are fulfilled. Abraham wrote in this chapter revealing how God is always faithful to keep His promises towards us, amazing how we forget this!