Bali Mahārāja, who put on his head the water washed from the lotus feet of the Lord, did not think of anything besides his promise, in spite of being forbidden by his spiritual master. The king dedicated his own personal body to fulfill the measurement of the Lord’s third step. For such a personality, even the kingdom of heaven, which he conquered by his strength, was of no value.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
नार्थो बलेरयमुरुक्रमपादशौच- मापः शिखाधृतवतो विबुधाधिपत्यम् । यो वै प्रतिश्रुतमृते न चिकीर्षदन्य- दात्मानमङ्ग स शिरसा हरयेऽभिमेने
nārtho balerayamurukramapādaśauca- māpaḥ śikhādhṛtavato vibudhādhipatyam | yo vai pratiśrutamṛte na cikīrṣadanya- dātmānamaṅga sa śirasā haraye'bhimene
SB 2.7.18