פירוש על קהלת 12:2

Before the darkening of the sun. Our Rabbis said that this שֶׁמֶשׁ refers to the forehead, which gives light and shines on a young man,³See Rashi in Maseches Shabbos 151b. but as he grows older, it becomes wrinkled and does not shine.⁴Alternatively, before becoming ill and bedridden. (Metsudas Dovid)

“Before the sun, the light, the moon, and the stars are darkened, and the clouds return after the rain” (Ecclesiastes 12:2);
“Before the sun…are darkened” – this is [a person’s] countenance; “the light” – this is the nose; “the moon” – this is the forehead; “and the stars” – these are the cheekbones. “The clouds return after the rain” – Rabbi Levi said two matters about this, one for Torah scholars and one for ignoramuses. One for Torah scholars: One comes to weep, and his eyes shed tears [copiously]. One for ignoramuses: One who comes to urinate, excrement emerges and precedes it.

The light. This refers to the nose, which is the form of the face’s features.

The moon. This refers to the soul, which provides a person with light, once it is taken away from him, his eyes cease to have light.

And the stars. These refer to the cheeks, the pomegranates of the face, called pomels [in O.F.] of the cheeks, which shine.

And the clouds return after the rain. The dimming of the light follow the tears of weeping for the many troubles that he experienced.⁵Alternatively, he returns to his weakness following a brief recovery. (Metsudas Dovid)