John Gill Commentary Luke 9:46

"And there arose a reasoning among them, which of them was the greatest." — Luke 9:46 (ASV)

Then there arose a reasoning among them
The Vulgate Latin, Syriac, and Arabic versions read, "a thought entered into them"; suggested very likely by Satan, which broke out into words, and issued in a warm dispute among them; and this was in the way, as they were travelling from Caesarea Philippi, to Capernaum; see (Mark 9:33) .

Which of them should be greatest ;
that is, "in the kingdom of heaven", as in (Matthew 18:1) in the kingdom of the Messiah, which they expected would be a temporal one: wherefore the dispute was not about degrees in glory, nor in grace; nor who should be the greatest apostle and preacher of the Gospel; but who should be prime minister to the king Messiah, when he should set up his monarchy in all its grandeur and glory.