The song has two characters, Eleanor Rigby and Father McKenzie. These two are connected by the church, in this case the actual church that Father McKenzie preaches at and Eleanor Rigby cleans. Here's where I tell my classes, artists never choose details indiscriminately. Every description is a clue, a symbol, a piece of the jigsaw puzzle. That is, often, the difference between good art and mediocre art.
Great artists know why they do what they do.
Back to the song. This is a great line to have students puzzle over. Eventually, with a little nudging, they'll see that this face is probably the face that she puts on to look beautiful, the jar being the makeup jar from which the face comes. When students see this, they really have pity for this woman. It might seem that both these two should get together but this is impossible.