Rabbi Yishmael addressed a possible misreading of the burglar law. The Torah seems to distinguish between day and night: (Exodus 22:1) discusses the thief "breaking in" (at night), and (Exodus 22:2) says "if the sun has risen upon him" (during the day). One might think the distinction is literally about time of day — killing the intruder is permitted at night but forbidden during the day.
Rabbi Yishmael rejected this reading by turning to (Deuteronomy 22:26), which discusses a different crime entirely: the rape of a betrothed maiden in the field. The Torah says: "For as a man would rise up against his neighbor and murder him, so is this thing." The comparison to murder is used to establish that in cases of imminent violence, the victim or bystander may use lethal force in defense.
The daylight-versus-nighttime distinction, then, is not about the clock. It is about the level of threat. At night, in the dark, a homeowner cannot assess the intruder's intentions. The doubt about lethal intent justifies defensive killing. During the day, with clear visibility, the homeowner can better evaluate whether the intruder poses a genuine threat to life. If the intruder is clearly there only to steal, lethal force is not justified.
The principle is not time but information. Darkness creates uncertainty about intent. Daylight reduces it. The Torah's day-night framework is really a threat-assessment framework.