Either,
1. In general, at the return of the set time then appointed, and used for the solemn service of God. Or,
2. At the end of the year, when there might be now, as there was afterward among the Jews, more solemn worship and sacrifices; the word days being often put for a year, as Leviticus 25:29 1 Samuel 1:3, 1 Samuel 27:7. Or,
3. More probably at the end of the days of the week, or upon the seventh and last day of the week, Saturday, which then was the sabbath day, which before this time was blessed and sanctified, Genesis 2:3. Cain brought an offering, either to the place appointed for the solemn worship of God, or to his father, who at that time was both king, and prophet, and priest. Or brought, i.e. offered.