A lot of ancient mantras are present in the Saṃhitā portion of the Vedas. The Saṃstrikeās are one of the most historical layer on the Vedas, and comprise a lot of mantras, hymns, prayers, and litanies. Metta meditation is actually a sort of Buddhist meditation. It’s often called loving-kindness meditation. https://emiliokapcr.blogstival.com/48961220/a-secret-weapon-for-mantra