Bhagavad Gita 10.35

बृहत्साम तथा साम्नां गायत्री छन्दसामहम्।मासानां मार्गशीर्षोऽहमृतूनां कुसुमाकरः॥

bṛhatsāma tathā sāmnāṃ gāyatrī chandasāmaham |māsānāṃ mārgaśīrṣo'hamṛtūnāṃ kusumākaraḥ ||

Among the hymns, I am the Brihatsaman; among meters, I am Gayatri; among months, I am Margasirsha; among seasons, I am the flowery season.

Of hymns, I am Brihatsama; of meters, I am Garatri; among months, I am Margasheersha (December); and I am Spring among seasons.

Our plain-language meaning of this verse is waiting for scholar review.