Help wiring a pendant light

The green wire gets connected to the copper wire from you fixture and to the copper wire from the ceiling. Use the wire nut from the old fixture. You also hook black to black and white to white. Make sure the power is off.

The bare wire is grounding/earthing the metal frame of the lamp, while the green wire which is part of the cable is grounding the handing pendant itself.

Since the frame and pendant are presumably connected only by the insulation of the hanging wire otherwise one or the other would have been un-earthed. Hence the two earthing wires need to be attached together and then to the earth from the supply wire.