Why is winning this fight important for Tom King?

Winning the fight is important because it will allow Tom King to put food on the table—literally. He and his family are in a bad way. They never have enough money and the children are often sent to bed early without any supper. Under the circumstances, Tom feels he has no choice but to put on his boxing gloves once again and take to the ring.
He's no longer what he once was; he's getting on a bit, and his movements aren't quite as graceful and steady as they used to be back in the day. But Tom reckons he can still fight. In any case, he doesn't have much choice. He's sick of his family going without food, including those nice, juicy steaks that he misses so much but can no longer afford.