Keyframe Animation Pause/Rest

In the image below I have a simple animation of a box moving through 4 key frames. How would I make the box pause or rest at one of the key frames for a certain amount of time completely stationary until moving again?

For instance in the image below, perhaps I want the box to pause for 3 seconds completely stationary at keyframe 2 before going through the rest of the animation path. After some tuotirals I stumbled upon I tried hold keyframe, but that made the box "jump" from one keyframe to another suddenly.

Thanks