But (αλλα). So usually, though it is open to question whether αλλα is adversative here and not rather, "Now then."

…

Go with them, doubting nothing.—The command was specially addressed to the perplexed questionings of the disciple. For a…

But on the roof of the tanner’s house, Peter was still so deep in thought about the vision that even their shouting and calling out his name failed…

Go, doubting nothing. The Scripture often uses this phrase when it expresses what kind of obedience faith should produce. So Paul, in Roma…

Arise, therefore, and get you down
From the top of the house where he was:

When we see our call to any service as clear, we should not be perplexed by doubts and scruples arising from prejudices or former ideas.