CHĀNDOGYA UPANISHAD · 3.16.3

अथ यानि चतुश्चत्वारिंशद् वर्षाणि तन् माध्यंदिनं सवनम् ।
चतुश्चत्वारिंशदक्षरा त्रिष्टुप् ।
त्रैष्टुभं माध्यंदिनं सवनम् ।
तद् अस्य रुद्रा अन्वायत्ताः ।
प्राणा वाव रुद्राः ।
एते हीदं सर्वं रोदयन्ति ॥

atha yāni catuścatvāriṃśad varṣāṇi tan mādhyaṃdinaṃ savanam ।
catuścatvāriṃśadakṣarā triṣṭup ।
traiṣṭubhaṃ mādhyaṃdinaṃ savanam ।
tad asya rudrā anvāyattāḥ ।
prāṇā vāva rudrāḥ ।
ete hīdaṃ sarvaṃ rodayanti ॥

The next forty-four years are the midday-libation. The Trishtubh has forty-four syllables, the midday-libation is offered with Trishtubh hymns. The Rudras are connected with that part of it. The Prânas are the Rudras, for they make all this to cry (rodayanti).

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)