Garudapurana 3.29.30

3.29.30

svāhākāro mantrarūpābhimānī svāheti saṃjñāmāpa sadaiva vīndra /
agnerbhāryāto buddhimān saṃbabhūva brahmābhimānī candraputro budhaśca //

Identifying with the utterance 'svāhā' in the form of mantras, she always attained the name Svāhā, O best of birds. / From the wife of Agni was born the wise Budha, the son of the Moon, who identifies with Brahmā.