Eddie is correct.
You can just daisy-chain the lights together by connecting all the black (hot) wires together and all the white (neutral) wires together with twist on wire-nuts. If your wiring also incudes a bare wire (ground) just connect those together as well. All of this should be done in the electrical junction box that is behind the first light. This assumes that you only have one switch that controls the light. If you have two switches (called a 3-way) that allow you to turn the light on or off, the wiring is different because you will have an addtional red wire called a Traveler.
If the wire from the second light will not reach back to the first light, you can add additional wire by installing a junction box w/cover in the attic (leave it exposed) and connecting the wires together with wire-nuts inside the box.
You should never hide junction boxes behind walls, etc and you should not just twist wires together (with or without wire-nuts) and leave them exposed. If you are not allowed to have junction boxes in in the attic, and your garage ceiling is drywalled, you can mount the box into the ceiling drywall and connect your wires inside the box. Then you can put a plain cover over the box, flush with the drywall (that is NOT considered a hidden junction box).
They make blue plastic boxes that have screws and wings that pop out and lock the box to the back of the drywall and do not need to be attached to a rafter or stud as is done in new construction.
...Rich
