Shatapatha Brahmana 11.4.2.7

11.4.2.7

atha haitattiryak yo'yaṃ yāvataivādatte tāvatā nidadhāti sa yamicennaiva śreyāntsyānna pāpīyāniti tasya yāvataivādadīta tāvatā nidadhyāttena sa naiva śreyānna pāpīyānbhavati

And the level one, indeed, it is when he concludes in the same tone in which he has begun: whoever should wish that any one should be neither more prosperous nor poorer, let him conclude for him in the same tone in which he has begun; and he will thereby become neither more prosperous nor poorer.