Genesis 4:8 New English Translation

⁸Cain said to his brother Abel, “Let’s go out to the field.”^[a] While they were in the field, Cain attacked^[b] his brother^[c] Abel and killed him.

Genesis 4:8 tc The MT has simply “and Cain said to Abel his brother,” omitting Cain’s words to Abel. It is possible that the elliptical text is original. Perhaps the author uses the technique of aposiopesis, “a sudden silence” to create tension. In the midst of the story the narrator suddenly rushes ahead to what happened in the field. It is more likely that the ancient versions (Smr, LXX, Vulgate, and Syriac), which include Cain’s words, “Let’s go out to the field,” preserve the original reading here. After writing אָחִיו (ʾakhiyv, “his brother”), a scribe’s eye may have jumped to the end of the form בַּשָׂדֶה (bassadeh, “to the field”) and accidentally omitted the quotation. This would be an error of virtual homoioteleuton. In older phases of the Hebrew script the sequence יו (yod-vav) on אָחִיו is graphically similar to the final ה (he) on בַּשָׂדֶה.
Genesis 4:8 tn Heb “arose against” (in a hostile sense).
Genesis 4:8 sn The word “brother” appears six times in vv. 8-11, stressing the shocking nature of Cain’s fratricide (see 1 John 3:12).

New English Translation (NET)