A.T. Robertson Commentary Mark 9:33

"And they came to Capernaum: and when he was in the house he asked them, What were ye reasoning on the way?" — Mark 9:33 (ASV)

In the house (εν τη οικια). Probably Peter's house in Capernaum which was the home of Jesus when in the city.

What were ye reasoning in the way? (Τ εν τη οδω διελογισζεθε; ). Imperfect tense. They had been disputing (verse 34), not about the coming death of the Master, but about the relative rank of each of them in the political kingdom which they were expecting him to establish. Jesus had suspected the truth about them and they had apparently kept it up in the house. See on Mt 18:1 where the disciples are represented as bringing the dispute to Jesus while here Jesus asks them about it. Probably they asked Jesus first and then he pushed the matter further and deeper to see if this had not been the occasion of the somewhat heated discussion on the way in.