In parts of the UK the equivalent is 'if we're spared'. Some people may decide this means that the person saying it is probably a miserable old codger, the sort of person who says "mustn't grumble" when asked "How's things?"
In America I sometimes hear a similar saying of "Lord willing" which is a shortening of a verse from James: "If the Lord wills, we shall live and do this or that."
I have always found the humility of Muslims saying "In sha'Allah" admirable. It's a beautiful way to remind ourselves that our fate -- and our life -- is not entirely in our hands.
This was also commonplace in Spain, traditionally. Some people, especially old ones, will say "si Dios quiere" literally every time they refer to any event in the future, even if it's just "see you tomorrow". Not doing so would be considered a "challenge" to God, or Fate, more generally.
Curiously, from "inshallah" Spanish got the word "ojalá", a very common term for expressing hope of something happening (and with no religious or any other "deep" connotation anymore; just like you'd use "I hope").
In Poland we have a saying "jeżeli Bóg pozwoli". "If god allows" which funyly shows that deep down people "understand" (as their pre-monotheistic ancestors "understood") that the God is the malevolent being that messes up your plans and ultimately kills you.
