'Once' in the Bible

And he also said to the crowds, "When you see a cloud coming up in the west, you say at once, 'A rainstorm is coming,' and so it happens.

when once the master of the house has gotten up and shut the door, and you begin to stand outside and knock [on] the door, saying, 'Lord, open [the door] for us!' And he will answer [and] say to you, 'I do not know where you are from!'

"And which of you who has a slave plowing or shepherding [sheep] who comes in from the field will say to him, 'Come here at once [and] recline at the table'?

And when you hear about wars and insurrections, do not be terrified, for these [things] must happen first, but the end [will] not [be] at once."

but I have prayed for you, that your faith may not fail. And you, [when] once you have turned back, strengthen your brothers."