Yoga Sutras 4.30
Patanjali, explained by Swami Vivekananda
तदा सर्वावरणमलापेतस्य ज्ञानस्याऽनन्त्याज्ज्ञेयमल्पम् ॥
tadā sarvāvaraṇamalāpetasya jñānasyā'nantyājjñeyamalpam
The knowledge, bereft of covering and impurities, becoming infinite, the knowable becomes small.
In plain words: When all coverings and impurities are gone, knowledge becomes endless. Compared to it, everything there is to know seems small.
Swami Vivekananda explains
Knowledge itself is there; its covering is gone. One of the Buddhistic scriptures defines what is meant by the Buddha (which is the name of a state) as infinite knowledge, infinite as the sky. Jesus attained to that and became the Christ. All of you will attain to that state. Knowledge becoming infinite, the knowable becomes small. The whole universe, with all its objects of knowledge, becomes as nothing before the Purusha. The ordinary man thinks himself very small, because to him the knowable seems to be infinite.