electric wire questions

Last December a tree fell on my powerline ripping a yard light wire out of the attic. Previously the yard light wire was just cut and the end wrapped in electrical tape. The other end was just 2 wires that look like they were connected to a switch. There was only 2 wires with no bare ground wire. The ripping loose of the wires also disconnected my bedroom light.

There are 3 wires in the attic and each wire has two wires. They look identical to me so I'm wondering how do I know which one is the ground and which is hot? The wiring is old and has the wire covered with a twisted cloth layer and a paper layer on top of that. One of the wires seems to have a slight silver color on the twisted cloth covering but I can't say for sure.

I checked the wires with one of those pens today and they are all hot. When I first looked at the wires after the storm there was a connection within a metal box. It was just a few wires left. My guess is that the box is where the now disconnected yard light connection was made. If I can't figure out the wiring I'm going to have to start cutting holes in the sheet rock.