Have you ever considered how many times God is recorded appearing to Abraham? How many times He reiterates His promise to him? The years in between?
Consider Genesis 18, when God (probably the Incarnate Christ) again appears to Abraham—this time in sandals and accompanied by two angels (we are told this later when they help Lot's family escape). It is not clear whether Abraham knows who he is hosting prior to this point, but Abraham hosts them, leading to an interesting exchange between Abraham, Sarah, one of the visitors who can read minds, and a laugh that later becomes a child whose name means “laughter.”
Most Western readings of this story put Sarah in a rather negative light, showing her laughter as mockery and inward thoughts as doubt. She then denies she laughed—out of fear of offending, most likely.
However, this may be a harsh reading of the story, especially since centuries later, Paul writes, “By faith, even Sarah herself received ability to conceive, even beyond the proper time for life, since she considered him faithful who had promised.” (Hebrews 11:11) It is, of course, possible that this encounter engendered her faith but Sarah’s faith existed before she conceived Isaac, not after.
Being childless is a great grief—especially in those days and especially for women. But Abraham and Sarah had received a great promise, reiterated several times, most recently resulting in both their names changing and the rather unprecedented event of the circumcision of the entire tribe Abraham ruled.
Side Note: This large-scale operation was not easily forgotten. The rite was performed on at least 318 trained men, their elderly parents, their male siblings, and their male sons. I am amazed at the size of this effort and the influence Abraham had to exert to accomplish this: no man gives up a piece of his manhood without an incredibly good reason. And no woman is keen on their husband being incapacitated for such a long time (Genesis 34:25 gives us an idea of how long and how intense the results on grown men).
If we read the response of the Lord with a sense of humor that Christ seems to display in the New Testament, the quip back to Sarah, “Is there anything too difficult for the Lord?” is less defensive and more of a teasing rebuke.
He again assures Sarah that at the appointed time, she will bear the promised child.
Regardless of how the story is read, Abraham laughed, later, for the joy of being told he would be a father. And when Isaac is born, Sarah says, “God has made laughter for me; everyone who hears will laugh with me.” (Genesis 21:6)
The key is in Paul's summary: "...since she considered him faithful who had promised." We must not fear the promise or the impossibility of the promised. Our God is faithful and at the appointed time, the promise will be fulfilled.
Where is your long-awaited promise?
Grace is faithful.