In English we tend to put the word holy in front of a lot of other words. It doesn’t mean that the word is religious, it is just an expression that we use to show surprise. It’s used much like the phrase Oh my gosh! Here are a few phrases that use the word holy.
Holy cow!
Holy moly!
Holy guacamole!
Holy smoke!
Holy mackerel!
Holy Moses!
There are a few other phrases that I left out, but only because they were a bit vulgar.
Love the illo!
Wow, thanks Aaron, coming from you that means a lot!!!