Sisera commanded the army of Jabin, king of Canaan, from a fortified base called Harosheth Haggoyim, and for twenty years his nine hundred iron chariots kept the Israelites subjugated^[1]. The prophetess Deborah persuaded the general Barak to face him in battle, and an Israelite force of ten thousand defeated Sisera's army at Mount Tabor, on the plain of Esdraelon; the biblical text credits the victory partly to the stars themselves fighting against Sisera and to a flood that swept his army into the river Kishon^[1]. Sisera fled on foot to the tent of Jael, whose husband's clan was allied with his own king, and so had every reason to expect shelter. She gave him milk, covered him, and promised to hide him from his pursuers. Once he slept, she killed him with the tools of her own domestic life, a mallet and a tent peg, rather than a soldier's weapon^[1][1].

Gentileschi chose to set the murder in an interior of grand palace architecture rather than the tent the text describes, built around a single dominant pillar that also carries her signature, an explicit declaration of authorship placed inside the composition itself^[1]. She reduced the scene to the two figures alone, discarding the wider biblical cast of soldiers and armies to concentrate entirely on the moment of physical and psychological confrontation between one woman and one sleeping man. The heads of both figures are unusually well preserved and painted with individualised, non-generic features, suggesting they were worked from specific models rather than stock types^[1].

Some art historians have identified an uncanny resemblance between Sisera's features and Caravaggio's own face, a painter who had died roughly a decade before this canvas and whose dramatic use of light and shadow shaped Gentileschi's entire visual language^[1]. Caravaggio's own history of violence, including killing a man in a duel and assaulting a Knight of Malta, was public knowledge in the artistic circles Gentileschi moved through. One reading of the painting treats the resemblance as a bold, coded statement: that having absorbed Caravaggio's style, Gentileschi now considered herself his equal or better. An alternative and more personal reading connects Sisera's face instead to Agostino Tassi, the painter who raped Gentileschi in 1611, a substitution scholars have also proposed for the vanquished men in her other biblical subjects^[1].