References – DN 3: With Ambaṭṭha 
“When the suttas describe a practitioner as “having gone beyond doubt,” (e.g. DN 3) what do they mean?” Answered by Ajahn Pasanno. [Doubt] [Sutta] // [Four Noble Truths] [Teaching Dhamma] [Ajahn Chah]
Story: An Ajahn Chah monk accused of a heavy offense. [Vinaya]
The Teaching and the Training [2018], Session 3, Excerpt 9
Readings by Ajahn Pasanno:
The Island by Ajahn Pasanno and Ajahn Amaro, Chapter 16, pp. 286-288:
Suttas: DN 3.2.21-22; SN 45.55; MN 2.9-11; SN 22.122.
Sutta: SN 22.122: Virtuous.