Write If condition as function

I'm trying to write an If condition as function and I'm not sure if this is even possible.

Following case:

File1

if_exit()
{
  if $1; then
      echo "$2"
      exit 1
  fi
}

File2

source File1

SUUSER=$(whoami)
if_exit "[ $SUUSER != 'root' ]" "Please run the script as root"

Explanation: I want to write a function, which includes If contitions (short example used here). Then I want to call that function with different things like mentioned above in the code example or:

if_exit "[ $(lsb_release -is) != 'Debian' ] && [ $(lsb_release -cs) != 'stretch' ]" "The script only works with Stretch"

Thanks in advance!