Bash – How to compare two files with a shell script

Given two files, I want to write a shell script that reads each line from file1 and checks if it is there in file2. If a line is not found it should output two files are different and exit. The files can contain words numbers or anything. For example :

file1 :

Hi!
1234
5678
1111
hello

file2:

1111
5678
1234
Hi!
hello

In this case two files should be equal. if file2 has "hello!!!" instead of "hello" then the files are different. I'm using bash script. How can I do this. It is not important that I need to do it in a nested loop but that's what I thought is the only way. Thanks for your help.