Canonical Reference: Karaniya Metta Sutta (Universal Loving-Kindness Discourse), Verses 145-147 Verified Source

“Whatever living beings there may be — feeble or strong, tall, stout or medium, short, small or large, seen or unseen, dwelling near or far, born or yet to be born — may all beings without exception be happy and secure in their hearts.”

Canonical Pali Original: Ye keci pāṇabhūtatthi, tasā vā thāvarā vā anavasesā; Dīghā vā ye mahantā vā, majjhimā rassakāṇukathūlā. Diṭṭhā vā ye ca adiṭṭhā, ye ca dūre vasanti avidūre; Bhūtā vā sambhavesī vā, sabbasattā bhavantu sukhitattā.

— Gautam Buddha
The Awakened One, Founder of Dhamma
Historical Setting & Context:

Pali Canon: Sutta Nipata 1.8, the universal aspiration of Metta (loving-kindness) embracing all sentient life without limitation.