«أُبَاحِثُ كُلَّ مَنْ جَلَّ وَقَلَّ»
I would engage in discussion with people of high and low standing.
Ubāḥithu is an imperfect verb from Form III, indicating discussion or scholarly exchange with another person. It need not mean an angry dispute.
Jalla wa qalla contrasts high and low degree. The narrator describes a search open to learning from different people, not only the most celebrated authorities.