Use Bash to Read File Then Do "grep" with The Line Against The File Itself

Use Bash to Read File Then Do "grep" with The Line Against The File Itself

I am trying to read a file using Linux Bash and then use "grep" to run
that line against the file itself. It seems not working to me...
#!/bin/bash
path=$1
while read line
do
var1=$(grep $line $path)
echo $?
exit
done < $path
The $? returns 1. What's going on here?