Brihadaranyaka Upanishad 5.14.7

5.14.7

tasyā upasthānaṃ gātryasyekapadī dvipadī tripadī catuṣpadyapadasi na hi padyase | namaste turīyāya darśatāya padāya parorajase'sāvado mā prāpaditiyaṃ dviṣyādasāvasmai kāmo mā samṛddhīti vā na haivāsmai sa kāmaḥ samṛddhyateyasmā evamupatiṣṭhate'hamadaḥ prāpamiti vā

Its salutation : ‘O Gâyatri, thou art one-footed, two-footed, three-footed and four-footed, and thou art without any feet, for thou art unattainable. Salutation to thee, the fourth, apparently visible, supramundane foot! May the enemy never attain his object!’ (Should the knower of the Gâyatri) bear hatred towards anybody, (he should) either (use this Mantra) : ‘Such and such—may his desired object never flourish !’—in which case that object of the person against whom he thus salutes the Gâyatri, never flourishes—or (he may say), ‘May I attain that (cherished object) of his !’