According to Sri Rudram this famous verse belongs to Vayu Purana
चमकं नमकं चैव पुरुषसूक्तं तथैव च
नित्यं त्रयं प्रयुञ्जानो ब्रह्मलोके महीयतॆ
camakaṁ namakaṁ caiva pauruṣasūktaṁ tathaiva ca nityaṁ trayaṁ prayuñjāno brahmaloke mahīyate
Meaning: A person reciting and applying daily the Chamakam, Namakam and Puruṣa Sūktam is honoured in the Brahma loka.
Chamakam, occurs in the Taittirīya Saṁhitā of the Kṛṣṇa Yajurveda4 in the 4th kāṇda, 7th praśna. It is so called on account of the recurrence of the word ca me directly translated as “and me”. After praying and identifying Rudra with everything in the Namakam, Camakam is usually recited immediately after, in which the devotee asks Him to give him everything, 347 things to be precise, coupled with the article ca (and) and the verb me kalpatām (be granted unto me). Camakam furnishes completely the idea of human happiness and defines in the highest degree the desires to be asked or to be granted. Camakam roots are firmly implanted in the worldly desires ultimately leading to the divine fulfilment.
Reason of not citing the original source is I ain't found Vayu Purana online in Sanskrit. It will be helpful if someone finds original sanskrit text of Vayu Purana online.