My landlord owes $1400 in gas under my name should I pay him rent or keep it and pay my gas?

Before I moved in to the house my landlord racked up $1400+ in a gas bill so when we put it in our name Nicor said that amount would be added to us regardless if it was our bill or not. I have given him the bill and asked them to pay it and they have not. I have not payed my rent and he is furious so do I pay him and worry about the gas later on which he probably wont pay judging from his personality so far? He threatens to evict us or give us a notice so I wondering what would happen when I go to court?