Dan shall be a serpent by the way, an adder in the path, that bites the horse's heels, so that his rider shall fall backward.
All Commentaries on Genesis 49:17 Go To Genesis 49
Rufinus of Aquileia
AD 411
The path indicates a more narrow way, which demonstrates that he does not walk along that wide and spacious way leading to death but along that narrow way full of obstacles leading to life. He bites the heel of the horse and so does what the apostle Paul said: “I pommel my body and subdue it, lest after preaching to others I myself should be disqualified.” He acts in this manner so that the rider may fall backwards. He always fears elations and heights and prefers his soul to fall from an evil height to an honest humility, in order to learn from Christ, who is modest and gentle in his heart. It is typical of those who progress to fear elation. And finally a very important apostle like Paul said, “A thorn was given me in the flesh, a messenger of Satan, to keep me from being too elated.” And so the soul, after being recalled from elation and led back to the humility of Christ, waits for the salvation of the Lord.