‘Then Laban and Bethuel answered and said, “The thing proceeds from Yahweh. We cannot speak to you good or bad.”
This is the decisive turning point. The decision is made. Laban acknowledges that Yahweh has clearly taken control and that he cannot therefore go against Him. The steward has put his case well. The writer wants us to know that even those who do not worship Yahweh have to admit His power. But there can be no doubt that they are also swayed by awareness of who Abraham is and his evident wealth.
“We cannot speak to you good or bad.” In this context this means ‘cannot say anything'. Sometimes however it specifically refers to a moral decision.
The mention of Laban first, when we would have expected Bethuel, is interesting. It is quite clear that he is heading proceedings. This suggests that Bethuel was in no condition to do so. He is included in the response out of courtesy and because the decision is officially his as head of the house, but he is clearly in no position to make it. It presumably indicates that he was suffering from some debilitating illness, possibly being in a near vegetative state.