Liquid soap freezes at around 12 degrees F while pure water freezes at around 32 F degrees.
The added ingredients in the liquid soap make it so that the freezing point of the liquid soap is lower than plain water.
So you might see the liquid soap begin to freeze around 32 however the liquid soap will not freeze solid until around 12 F degrees or even lower.
So if you have liquid soap in an unheated garage or unheated basement etc then make sure to bring the liquid soap into a heated space during extreme cold weather because it can freeze up and it looses it's effectiveness at cleaning.
You can still use liquid soap after it freezes but it doesn't work as good as it would before it froze.