Escape spaces in bash script

I am trying to do something in a bash script whenever a file in a directory I am iterating over contains a string using grep. The problem comes in where a subset of the files in the directory contain spaces in the name. Therefore, I have tried to replace the spaces with escaped spaces in place using sed:

if grep -c "main" ${source} | sed 's/ /\\ /g'; then
  # do something
fi

However, I still get the error:

grep: /Users/me/Desktop/theDir/nameWith: No such file or directory

grep: spaces.txt: No such file or directory

What am I doing wrong?

Answer

You should quote the name of the file being grep'ed:

if grep -c main "$source" ; then
  # do something
fi

...assuming $source is the name of a file. If $source is the name of a directory, I'll need more information about what you're trying to do.