In the evening he was shut up by the shepherd in the fold; the gate was closed, and the entrance made thoroughly secure.

“晚上，他被牧羊人关进了羊圈；大门被关上，入口被彻底加固。”

这里的 "shut up" 表示被关进、关起来，"fold" 指的是羊圈，"entrance made thoroughly secure" 意味着入口被完全封锁或加固，确保安全。