In plain words
You watch films. At first, all you see is a white screen. You cannot sit there just looking at that screen, can you! So you wait for something. For what? For the pictures. When the pictures come, you watch them happily. Do they stay still at all? No. They go away. Again pictures come. In this way the pictures keep coming and going. But the screen does not come, does not go. It stays steady. That is ‘Brahma satyaṃ, jagat mithyā’. Mithyā: jagat is ja, coming, and gat, going. Coming and going: this is the jagat. The pictures come, they go. That is the jagat. Brahma satyaṃ: the screen is always there. No one cares to look at that Satya. When the pictures come, though, they look at that screen. The very next minute he spoke another truth of Vedānta. ‘Sarvaṃ viṣṇumayaṃ jagat,’ he said. ‘All is Viṣṇu! All is God!’ he said. The paṇḍitas were astonished. A few minutes before, he had said ‘Jagattu mithyā’, ‘Brahma satyaṃ’. Now he is saying ‘Sarvamu viṣṇumayaṃ jagattu’. Is that true, or is this true? ‘That is true, and this is true,’ said Śaṅkara. The pictures come, they go.
Again birth, again death, again lying in a mother's womb; in this saṃsāra, so hard to cross, by Your grace bring me to the further shore; protect me, O Murāri!
All is mithyā. Being born, dying: this goes on for ever. But the jagat is not born, it does not die. Here is another example for ‘Sarvaṃ viṣṇumayaṃ jagat’. There is the screen. Pictures fall on the screen. You see only these pictures. When these pictures come, where is that screen which is there for ever? The screen is right there, mingled with the pictures. Without the screen the pictures themselves cannot be seen. So what is behind is the screen. Because the screen is behind, we see the pictures. So this screen is in the pictures too. The eternal Īśvaratva is one with the passing pictures. That is ‘Sarvaṃ viṣṇumayaṃ jagat’. Without the screen there are no pictures. The screen is in the pictures. That is the Ātmatattva.