Literature: Mormon shapes Samuel’s story so that it parallels Nephi’s. Nephi was returning home when the Lord instructed him to call the people to repentance. He instantly obeyed, without even going to his house. (See commentary accompanying Helaman 10:6–12.) Samuel is also going home when the voice of the Lord instructs him to return. He obeys instantly.
Whether these events happened exactly as recorded (and there is no reason to doubt them), the importance of this parallel is that Mormon made sure it was part of his record. As editor, Mormon has many options available in recording events. In this case, he made Samuel’s call parallel to Nephi’s, with the effect of equating Samuel with Nephi. Nephi was a known prophet of an important lineage, but Samuel is no less called of Yahweh, no less worthy, no less entrusted with a vital message of repentance.
The Zarahemlaites have already heard and rejected Samuel’s preaching. Now they physically prevent him from entering the city. Samuel refuses to have his commission from Yahweh thwarted and preaches from the city wall.