Śāṅkhāyana (Kauṣītaki) Āraṇyaka 7.6

7.6

ŚĀ 7,6
agniḥ pūrvarūpaṃ candramā uttararūpaṃ vidyut saṃhiteti sūryadattaḥ | ityadhidaivatam | athādhyātmam - vāk pūrvarūpaṃ mana uttararūpaṃ satyaṃ saṃhitā | sa ya evam etāṃ etāṃ saṃhitāṃ veda saṃdhīyate prajayā paśubhir yaśasā brahmavarcasena svargeṇa lokena sarvam āyur eti ||

Agni is the first member, the moon the second member, lightning the continuous text: thus [holds] Sūryadatta. Thus with respect to the deities.
Now with respect to the self. Speech is the first member, mind the second member, truth the continuous text. He who thus knows this continuous text is joined with offspring, with cattle, with renown, with brahminical splendour, with the heavenly world; he attains a full lifespan.