Often times when I'm searching for something in grep, I'll turn on the context option (-C). So if you want context based on searching for a keyword you can do it like this:
grep -C3 searchpattern file
That will give you 3 lines above and 3 below of context. Increase/decrease as necessary. You can also go specific amounts above and below with -A number (above) and -B number (below). If you want to do it specifically by line number, you could try the nl command for numbering the lines then grep -C3 based on matching the number. For instance to get line 26:
nl -n ln -ba inputfile | grep -C3 "^26 "
Its a bit tricky though because you have to pass those formatting options to nl to get it to not put tabs and stuff in the numbering format. grep also has a line numbering option (-n) and you could pass things through grep twice like this based on matching nothing first (the double-double quotes) then the line number second:
grep -n "" inputfile | grep -C3 "^26:"
Just make sure you use some context in your regex for matching the line number so that you don't also match things like 126 or 260, etc.