Tzava'at Harivash 11

I.e., the concept of “service for the sake of Above” (see sect. 2-3). This is the principle of “Acknowledge Him in all your ways” (Proverbs 3:6; see below, sect. 94), and “Let all your deeds be for the sake of Heaven” (Avot 2:12), as explained in Shulchan Aruch, Orach Chayim:231.

True service of God implies total disregard of self, to the point of bitul hayesh, self-negation (see below, sect. 52-53). This excludes the expectation of any sort of reward (material or spiritual), the pursuit of spiritual attainments (cf. below, sect. 47), let alone a sense of self-satisfaction. All these are peniyot (sing. peniyah), ulterior motives of ego-centricity that must be shunned (see below, sect. 15, 42, 55, 77 and 92).