عَرَضْتُ الْحَوْضَ عَلَى النَّاقَةِ
I presented the trough to the she-camel.
عَرَضْتُ النَّاقَةَ عَلَى الْحَوْضِ
I presented the she-camel to the trough.
The source offers the second expression as the inverted counterpart of the first. Presenting water to an animal is the ordinary sense; speaking of presenting the animal to the trough reverses what is presented and what receives the presentation.
The intended outcome remains that the camel should drink. Context and knowledge of the ordinary situation make the reversed wording understandable.