Responsa do Rodzaju 12:22

They responded: Both these and these are sinners. The people, who do not call on the priests to bless them, seem like they do not care for the blessing of their Heavenly Father. And the same can be said for the priests, who do not recite the blessing on their own accord²This is similar to the opinion of R. Manoach ben Yaakov, cited in Beit Yosef, Orach Chaim 128. For the Torah says "I will bless those who bless you" (Genesis 12:3) - this implies that the inverse is also true.