He found a fresh jawbone of a donkey, reached out his hand, took it, and killed 1,000 men with it.

Then Samson said:

With the jawbone of a donkey
I have piled them in a heap.
With the jawbone of a donkey
I have killed 1,000 men.

When he finished speaking, he threw away the jawbone and named that place Ramath-lehi.