From the Bible:

“God is a spirit, and they that worship Him must worship Him in spirit and in truth.”

From the twelfth Chapter of the Bhagavad Gita:

“Those who, ever steadfast, worship Thee as devotees, and those who contemplate Thee as the immortal, unmanifested Spirit – which group is the better versed in yoga?”

The blessed Lord replied: “Those who, fixing their minds on Me, adore Me, ever united to Me through supreme devotion, are in My eyes the perfect knowers of yoga. . . .

“Those whose strict aim is union with the Unmanifested choose a more difficult way; arduous for embodied beings is The Path of dedication to the Absolute.”