It is based on 1 Samuel 2.  In this episode, Hannah prays.  In this prayer she not only praises God but also presents God as a God of reversals.  Simply, God trumps human conventional power with unconventional power.  After the prayer, we learn that Samuel is growing religiously, that Eli blesses Hannah and her husband, that this blessing eventuates in more children, that Eli’s sons were corrupt priests, and that the priestly House of Eli will soon experience judgment.