John Gills Exposition of the Bible Commentary - Genesis 38:8
And Judah said unto Onan ,.... Some time after his brother's death: go in unto thy brother's wife, and marry her ; Moses here uses a word not common for marriage, but which was peculiar to the marrying of a brother's wife according to a law given in his time: it appears to have been a custom before, and which the patriarch might be directed to by the Lord, in such a case when a brother died, and left no issue, for the sake of multiplication of seed, according to the divine promise, and... read more
Matthew Henry's Complete Commentary - Genesis 38:1-11
Here is, 1. Judah's foolish friendship with a Canaanite-man. He went down from his brethren, and withdrew for a time from their society and his father's family, and got to be intimately acquainted with one Hirah, an Adullamite, Gen. 38:1. It is computed that he was now not much above fifteen or sixteen years of age, an easy prey to the tempter. Note, When young people that have been well educated begin to change their company, they will soon change their manners, and lose their good education.... read more