Also, your question leads me to believe that you have no knowledge of how ohms work.
Well an amplifiers rating of ohms is a measure of how close to a dead short you can get it, 0 being a dead short(like touching the pos and neg wires together), now your home amp is rated to deliver power into a minimum load of 8 ohms and your sub is rated to put a load of 4 ohms on the amps outputs, so if you hook the sub up to the amp you will run it alot closer to a dead short than it can handle.(this is a really simple way of putting it)
Now you can wire the 2 subs in a SERIES circuit, to do this you take the positive wire from your amp and hook it up to the positve on the sub, now take the nagative from that sub and wire it to positive on the next sub and then back to the amps negative. Think of it as a path, the electrons go marching into the first voice coil and then out to the second and then back to the amp, as the electrons march through the first voice coil they encounter 4ohms of resistance when they go into the next coil they encounter 4 more ohms of resistance, giving a total resistance of 8ohms, which your home amplifier can handle.
P.S.- I sincerly hope that your concept subs bring you more joy than mine did . //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif