Seeing is here understood, either,
1. Properly, and so God would cut off the occasions of further filthiness. Or rather,
2. Improperly, for touching her or lying with her; for,
1. The sense of seeing is oft put for other senses, as for hearing, Genesis 42:1, compared with Acts 7:12 Exodus 20:18 Revelation 1:12; and for touching, as 1 Thessalonians 20:25,29.
2. That act is expressed by words parallel to this of seeing, as by uncovering, or discovering, and by knowing, Genesis 4:1.
3. So it is directly explained in the following words, he hath uncovered his sister's nakedness, which manifestly signifies lying with her.
4. It is not probable that an equal punishment would have been appointed to an immodest sight, and to the highest act of filthiness.
5. Nor seems there to be any reason why this crime should be restrained to this rather than to any other relations, when it was as great, yea, a greater crime in some other relations. In the sight of their people, i.e. publicly, for the terror and caution of others.