Many cat owners, who genuinely love their pets, have no idea what declawing means to their animals.
  Declawing means far more than leaving your pet defenseless against an attack outdoors.
It means:
The severing of ligaments and tendons that bring pain.
The creating of an imbalance that can lead to injury.
A change in personality and temperament.
A cat may go berserk, bite and growl. It means you, as the cat owner, have renounced the responsibility you assumed when you fell in love with that kitten or cat.

How Important are a Cat's Claws?

Dr. Louis J. Camuti, a practicing veterinarian for 58 years, puts it this way:
  "I wouldn't declaw a cat if you paid me $1,000 per Nail!"
  Have you often wondered at a cat's remarkable grace and agility, its faultless sense of balance?
  To a great extent, this is due to its ingeniously designed retractable claws that allows it to establish footing for walking, running, springing, climbing, or stretching.

First, it awakens from anesthesia, with its feet throbbing under the bandages; next it has pain and then it finds it has trouble walking.
  The physical effects of declawing is gradual weakening of the muscles of the legs, shoulders and back. Balance is impaired. Emotionally cats feel defenseless and thus live in a constant state of stress, making them more prone to disease.
  Despite its grace, a cat is not sure-footed. Without the lightning-quick ability to grasp with its claws, it can easily be injured in a fall.
  Deprived of its claws, a cat may turn to its only other form of defense - its teeth. It is fairly common for a declawed cat to become a biter. They do this out of fear and frustration.

Provide your Cat with His Own Furniture.

The scratching post should be rough and course. Buy a sisal (a harsh, scratchy hemp product) scratching post or make your own inexpensively. Just nail a piece of 2x4 board to an inch-thick square base and cover both pieces with a carpet remnant (tightly woven pile is best). You can even use a tree branch or a board angled against a wall and secured so it won't fall over.

"To protect the furniture," is the most common reason.
  "To keep my cat from scratching us when we try to play with him," is another.
  Scratching is a normal characteristic of a healthy cat. It exercises the foot muscles and removes dead tissue from the nails. It also has a soothing, comforting effect that creates a tranquil disposition.

When a kitten starts to scratch furniture, gently pull it off and place its front claws on the scratching post. Keep the post in an easily accessible place so the cat becomes accustomed to using it. 
  If an older cat persists in scratching furniture, give it a squirt of luke-warm water from a child's water gun. Spray it in any place but in the face. At the same time, say a sharp "NO." Then take it back to its scratching post.
Shake a small amount of pleasantly scented bath oil on a piece of cotton. Attach the cotton to the part of the furniture that the cat scratches. It will repel the cat as long as the aroma remains.
  Your cat gives you love and loyalty. It's the most it can give. You owe it one thing more - to leave its paws and claws.