Finishing the 5th chapter, and beginning the 6th, with a discussion of the blessing on the new moon -- a festive time. And a time of sanctification of the months: The is my God, and I will glorify him. Plus, defining what Rosh Chodesh is - the human involvement in calling the month. Also, the last discussion of chapter 5 - on an even vote to acquit, when there aren't the numbers needed for a guilty verdict - with the goal of a clear decision, perhaps preferable for lenient judges. Also, the 6th chapter -- on executions. Note that the execution becomes a mitzvah and therefore provides atonement for the individual in need of atonement... The new mishnah explains the process of what to do in the process of the beit din, for example, including one man with flags to wave down the sages for the sake of a potential stay of execution. Plus, the historical/biblical set-up of the camp.