In moments of danger during a bullfight, a strong, expert matador will grabs the bull by the horns and so prevent it from tossing him.
By extension the proverb means that when faced by perils or difficulties we should meet them fearlessly, not try to to evade them.
As the jeep rounded the bend, the soldiers in it saw that the road ahead was blocked by a mob of rebels.
‘What do I do now?’ asked the driver.
‘Step on it,’ said the corporal in charge, ‘and cut straight though ’em.’
The driver bought down his foot on the accelerator, the jeep shot forward, the insurgents broke up in disorder and scrambled up the banks on either side of the road.
‘Always take the bull by the horns,’ said the corporal with a satisfied grin as they continued on their way.