When a living creature sees his own Soul in all things, and all things in his own Soul, he is said to attain to Brahma.
सर्वभूतेषु चात्मानं सर्वभूतानि चात्मनि। यदा पश्यति भूतात्मा ब्रह्म सम्पद्यते तदा॥