This paper searches for a clue to the understanding of the so-called ignorance (avidyā / avijjā) and everything (sarva-bhāva / sabba-bhava) from the perspective of wisdom endowed with insight into emptiness (prajñā / paññā) based on the Āgama-sūtras and Prajñāpāramitā-sūtras. On the one hand, the inquiry as such may unfold the reason why sentient beings are ignorant of reality and illuminate the constitution of everything in the world. On the other hand, this exploration may exemplify that wisdom endowed with insight into emptiness is characteristic of being proficient in Buddhist practices. This paper is composed of six sections. The first is an introduction that elucidates the theme and the outline of this paper. Section two discusses how the Āgama-sūtras expound ignorance and everything from the perspective of conditioned co-arising (pratītya-samutpāda / paticca-samuppāda). Section three presents a clue to illuminate wisdom endowed with insight into emptiness from the angle of how perception can operate differently along the progression of cultivating śamatha and vipaśyanā leading to penetrating insight. Section four focuses on one specific passage of the Aṣṭasāhasrikā Prajñāpāramitā to illustrate how the scripture explicates ignorance and everything in terms of wisdom endowed with insight into emptiness. In the light of wisdom endowed with insight into emptiness that discerns the digression of ignorance and expounds the reality of everything, section five examines and figures out some cruxes where mediocre beings digress while engaged in cognitive and emotional activities. Section six concludes the main points of this research.