Verse 13
Under oaks - אלון allon, from אלל alal, he was strong. Hence, the oak, in Latin, is called robur; which word means also, strength, the oak being the strongest of all the trees of the forest.
The shadow thereof is good - Their "daughters committed whoredom, and their spouses committed adultery."
1. Their deities were worshipped by prostitution.
2. They drank much in their idol worship, Hos 4:11, and thus their passions became inflamed.
3. The thick groves were favorable to the whoredoms and adulteries mentioned here. In imitation of these, some nations have their public gardens.