You should get a quality bar and chain oil. Here's some – take your pick. Barring that (no pun intended), you can use SAE30W motor oil in a pinch. It's not as viscous (that means thick) as bar and chain oil, so it will fling itself everywhere and you'll end up using more (and getting your clothes oily), but at least you won't have to stop work if you are out of bar and chain oil. Consider yourself warned.