Vayishlach 5773

The Kli Yakar explains that the Yetzer Hara is like a fly that can't damage one's skin, but looks for an opening. This is how the angel was able to attack Yaakov, he found a small deficiency in Yaakov's middos. Yaakov had gotten very rich by Hashem and this caused him to not be satisfied with what he had (but very slightly). This is why he crossed over the river to retrieve his small items. The angel noticed this "opening" and attacked Yaakov.