Since here in 𝓟 either reading, with or without the behold, is possible, scribe 2’s supralinearly inserted behold (miswritten as bhold ) undoubtedly represents the reading of the original manuscript. Elsewhere in the text, there are four instances of the precise phraseology “for I say unto you” and five of “for behold I say unto you”.
Summary: Maintain in Alma 10:10 scribe 2’s corrected reading in 𝓟: “for behold I say unto you”.