How do I attach a weapon to a rig to preview how it looks when the animation is played while its held?

[justin2710 (Him)]

1. What do you want to achieve? Keep it simple and clear!
   I want the animation editor to play while the tool moves along the hand.
2. What is the issue? Include enough details if possible!
   Every time I play the animation it only moves the arm.
3. What solutions have you thought of so far?
   None

i want to see what a animation plays while a tool moves with the arm.