Both are about something temporary. "Borrow" meaning something you're getting temporary period. "Lend" meaning something you're giving for a temporary period. "Hey, can I borrow a pencil?" "Yeah, I think I have one to lend to you."

They're two different perspectives of the same event. Sue needs a hammer. Jane has a hammer. If Jane lets Sue use the hammer for a while you could say: Sue is borrowing the hammer from Jane or you could say: Jane is lending the hammer to Sue Both of those describe the same thing. It's similar to the difference between giving and getting.