1. Put the chopped up beef and cream cheese in a bowl and using a fork, blend until mixed together well. Add the horseradish, black pepper, and lemon juice and mash together until smooth.
2. Cover and refrigerate to let flavors mix for about 1 hour.
3. Clean celery sticks and cut into snack size 'logs' about 2 bites size.
4. Remove cream cheese spread from refrigerator and allow to sit at room temperature for a couple minutes, then stir again.
5. Spread cream cheese mixture into the celery stalks and serve as a snack. You'll have enough celery sticks to serve about 6 to 10 people, depending on the situation.