Mac Terminal command - Find string and print with surrounding line

I have been testing using ack, sed, grep trying to search through files in a directory to find a particular string. I am looking through my database files to check to see if passwords are listed in clear text. So far, I have been able to use this command: grep -Ri "search_string" /path_to_Folder However, this only outputs the files that contain the string. I want to go one step further and print out the line around the string so I don't have to go in and search each file. I hope that make sense. Thank you so much.