In plain words
Emperor Bali recognised that Satya. ‘I am the giver; this is my good fortune. How fortunate I am!’ he thought. He kept extolling his own good fortune. But his guru, Śukrācārya, stood in his way: ‘The one who stretches out his hand before you asking for a gift is not just an ordinary brāhmin. He is Śrīman Nārāyaṇa Himself,’ he said. Then Emperor Bali said: ‘Gurūjī! For me no one is greater than God. I will give up even my guru, but I will not give up God. In the world there are those who give land. There are those who give learning. There are those who give food. There are those who give money, gold, goods and vehicles. These gifts are not great.’ Saying this, he made a gift of his own self to Vāmana! Regarding this gift as the offering of the self, Emperor Bali gave himself.
My wealth, my wife and all I have, everything, is offered to You; O sole Lord of all the worlds, protect me, who have taken refuge in You.
‘All that I have is Yours,’ he said, and offered it. What is the inner meaning of Vāmana, who sought three paces of ground, covering the earth with one foot and the sky with the other, and setting the third pace on Emperor Bali's head? For the One who trod the whole world with one foot, Emperor Bali was surely in that very world! Where could his head be, separate and apart? That is, there is another inner meaning to this. It means that He took over not only the kingdom of the earth and the kingdom of heaven but the kingdom of the mind as well. So Vāmana received from Emperor Bali the kingdom of his mind. Manas alone is the root cause of this whole world. ‘Manaeva manuṣyāṇāṃ kāraṇaṃ bandhamokṣayoḥ’: we must bring that Manas under control. Only then does one go beyond Manas. Mokṣa comes only to the one who has gone beyond Manas. In this way Vāmana bestowed Mokṣa on Emperor Bali. He took over his kingdom of the mind as well.