Vishnu

Traditional Vaishnava mantra (Taittiriya Aranyaka / Narayana Upanishad tradition)

ॐ नमो नारायणाय

Om, salutations to Narayana.

Traditional dhyana verse preceding the Vishnu Sahasranama (Mahabharata, Anushasana Parva tradition)

शान्ताकारं भुजगशयनं पद्मनाभं सुरेशं विश्वाधारं गगनसदृशं मेघवर्णं शुभाङ्गम् । लक्ष्मीकान्तं कमलनयनं योगिभिर्ध्यानगम्यम् वन्दे विष्णुं भवभयहरं सर्वलोकैकनाथम् ॥

Of tranquil form, resting on the serpent-couch, lotus-navelled, lord of the gods; support of the universe, boundless as the sky, cloud-dark and radiant of limb; beloved of Lakshmi, lotus-eyed, reached by sages only through meditation — I bow to Vishnu, remover of worldly fear, sole lord of all realms.

Traditional invocatory verse, Mahabharata tradition

शुक्लाम्बरधरं विष्णुं शशिवर्णं चतुर्भुजम् । प्रसन्नवदनं ध्यायेत् सर्वविघ्नोपशान्तये ॥

One should meditate on Vishnu, clad in white, moon-hued, four-armed, and serene-faced, for the pacifying of all obstacles.

Mahabharata, Anushasana Parva 149 (preamble to the Vishnu Sahasranama)

यं ब्रह्मा वरुणेन्द्ररुद्रमरुतः स्तुन्वन्ति दिव्यैः स्तवैः वेदैः साङ्गपदक्रमोपनिषदैः गायन्ति यं सामगाः । ध्यानावस्थिततद्गतेन मनसा पश्यन्ति यं योगिनो यस्यान्तं न विदुः सुरासुरगणा देवाय तस्मै नमः ॥

Whom Brahma, Varuna, Indra, Rudra and the Maruts praise with celestial hymns; whom the Sama chanters sing through the Vedas with their limbs, syllables, sequences and Upanishads; whom yogis behold with minds fixed in meditation; whose end neither gods nor demons have known — to that God, salutations.