In the fourth aliyah Yosef sends his brothers away in wagons carrying the good things of Egypt. They go up to their father and tell him that Yosef is still alive and ruler of Egypt. At first he doesn't believe them, but then he sees the wagons, and believes Yosef is alive. This is because the word for wagons in Hebrew is agala, which is similar to the word egla, as in egla arufa. Egla arufa refers to the parsha about the Kohanim breaking the heifer's neck, which was the section of Torah Yosef and Yakov were studying together 22 years earlier when Yosef disappeared. In this way Yosef gave Yakov a sign that he was still alive.