How do you wire a fixture that had two hot and two neutral wires?

To install a new fixture to replace the one that was removed reconnect the two hot wires together and then reconnect the two neutral wires together. Place the two wires from the new fixture to the corresponding wire colours that you just spliced together. This wiring should be down stream from the light switch. When the switch is turned on the new fixture should light. If this is not the scenario of your question then more information needs to be given.