prove a point

:  to learn or find out by experience

:  to test the truth, validity, or genuineness of

:  to test the worth or quality of

:  an individual detail :  item

:  a distinguishing detail

:  the most important essential in a discussion or matter

:  to furnish with a point :  sharpen

:  to give added force, emphasis, or piquancy to

:  to scratch out the old mortar from the joints of (something, such as a brick wall) and fill in with new material