Abib 13 marks the beginning of the time of unleavened bread, a period during which the Jews disposed of all leavening and prepared unleavened bread for the Passover meal. On this day, they would burn the leaven by 10:00 am, and they were not allowed to eat anything leavened after 11:00 am, with the unleavened bread baked and ready for the Passover by 3:00 pm. This day, before the Feast of Unleavened Bread officially begins on Abib 15, is when preparations for the Passover sacrifice were underway, setting the stage for the events that followed as Abib 14 began after sunset.

On the evening of the 13th of Abib/Nisan, which until the evening of the 14th was known as the preparation for the Passover, every head of a family searched for and collected all leaven by the light of a candle. Before beginning this search, a benediction was pronounced, acknowledging God's command to remove the leaven. After the search, any remaining unseen leaven was declared null and accounted as dust. According to historical sources, the leaven was burned by 10 a.m. on the 13th, and no one was allowed to eat leaven after 11 a.m. By 3 p.m., the unleavened bread was baked and ready for the Passover. This day, the 13th, was considered the first day of the year when leaven was required to be put out, marking the beginning of preparations for the Passover and the Days of Unleavened Bread. In this context, the disciples approached Jesus on the 13th, asking where He wanted them to prepare for Him to eat the Passover, aligning with the necessary preparations before the lamb was to be slain at ben ha arbayim after the going down of the sun on the 13th, which marked the start of the 14th.

The following is a concise rewrite of the sections related to Abib/Nisan 13 as they pertain to the broader context of the provided material, maintaining the original tone and focusing solely on the content within the text. Regarding the timing of events leading to Passover, the lamb was to be killed at the very beginning of the 14th day of Abib/Nisan, during the period of remaining light as the 13th ended with sunset. This specific moment is identified as ben ha arbayim, a precise time immediately following sunset, marking the transition from the 13th to the 14th, during which the Passover day began. This period, synonymous with twilight, is distinguished from the more general term ba erev, which covers a broader span of time and can indicate either the beginning or end of a day. The distinction is critical, as it sets the boundary for the start of Passover observances at the close of Abib/Nisan 13, ensuring the proper sequence of events as the 14th commences.