"If you don't know me by now, you will never, never, never know me" -- the lyric opens with a verdict, not a question. He is not asking for understanding. He is stating that the window for understanding has closed. The song is a statute of limitations on patience, the moment when one person realizes that the other has been sharing space without sharing comprehension. "All the things that we've been through, you should understand me like I understand you" -- the math is simple. If you have been through the same experiences and come away with no deeper knowledge of who I am, the problem is not time. The problem is attention. You were there but not present.

Harold Melvin & The Blue Notes recorded it first in 1972, taking Teddy Pendergrass's lead vocal to #3 on the Hot 100 and #1 on the R&B chart.