The pairing with Parashah Vayera, whose central episode is the announcement that Sarah, long past childbearing age, will bear a son within the year, rests on the Shunammite woman's parallel story: a woman similarly beyond the ordinary age for children is told by a man of God that she will have a son, reacts with disbelief much as Sarah does, and then receives exactly the promised child at exactly the promised time.
The parallel extends further than the announcement itself. Sarah's laughter at the news in the parashah and the Shunammite woman's own hesitant response to Elisha's promise both frame a miraculous birth as something the intended mother initially receives with doubt rather than immediate faith, a shared human reaction the two accounts, centuries apart, treat almost identically.
The haftarah's second episode, the boy's death and Elisha's revival of him, extends the parallel with the Akedah, the binding of Isaac that closes this same parashah: in both accounts a promised, long awaited son is brought to the edge of death and then restored, a shared shape of loss averted that the rabbis selecting this pairing evidently recognized across two very different narrative settings.