spur (noun) – a sharp object attached to a rider’s boot to make the horse go (faster). Or: something that motivates.
Spur (on) (verb) – to make a horse go (faster), to motivate/stimulate

Vince Alongi

Examples:

The rider has spurs attached to his boots, but he claims he never strikes his horse with them.

Lack of work could be a spur for her to start doing some marketing.

The horse is spurred on by the thought of his nice, warm stable at the end of the ride.

Elsa is spurred on by her manager’s promise she will get a promotion.

If the teachers fail him now, it won’t spur him to work harder.

Personal gain had spurred the politician to speak to the congress, not national interest.