The grep command recoginzes some special characters to specify exactly where to search for your pattern. If you just want to look for a certain phrase use fgrep instead.
Search any file in the current directory:
fgrep "put your phrase here" *
Recursively search any file in the current directory and subdirectories:
fgrep -r "put your phrase here" .
For a case-insensitive search, add the -i option before the search phrase. To just output the file names containing the phrase add the -l option.