LEV563 Spiritual welfare is a by-product of love and of consideration for all. It is born of a minimizing of the good done for another and a maximizing of the good done by another (Derekh Eretz Zuta; Abot d'R. Nathan, passim). It will express itself in altruistic friendship, ever ready to be the first to greet others (Abot iv. 20) and regarding the honor of another as equivalent to one's own (Abot 15). Rabbi Johanan b. Zakkai was always the first to greet a person, be he a non-Jew (Berachot 17a); to be polite to others is equivalent to being polite to the Shechinah (Erubin). If one has nothing to offer a poor man save courtesy and a smiling face, it is good enough; life has shown these things to be worth more than treasure (Abot d'R. Nathan). Nothing is more injurious to moral well-being then to hate another inwardly [this verse; Arakhin 16a], and to take vengeance is a boomerang; for both suffer. If we are to love another as ourselves, the logical inference is that to hurt another, is like cutting off our right-hand because it has injured our left (a striking thought of the Yerushalmi Ned. ix).