John Gill Commentary Ruth 3:9

"And he said, Who art thou? And she answered, I am Ruth thy handmaid: spread therefore thy skirt over thy handmaid; for thou art a near kinsman." — Ruth 3:9 (ASV)

And he said, who are you ?
&c.] He spoke quick and short, as one displeased, or however surprised and frightened, just coming out of sleep, and in the night:

and she answered, I am Ruth your handmaid ;
that had gleaned in his fields with his maidens, and with whom he had conversed there, and knew her by name:

spread therefore your skirt over your handmaid ;
which seems to account for the reason of her uncovering his feet, or turning up the skirt of his garment that was upon them; not through wantonness and immodesty, but to direct him, when opportunity offered, to spread it over her as a token of his taking her in marriage, and of her being under his care and protection, and of her subjection to him; so the Targum, ``let your name be called upon me to take me for a wife,''

Whether the custom now used with the Jews at marriage, for a man to cast the skirt of his "talith", or outward garment, over the head of his spouse, and cover it, was in use so early, is questionable; and yet something like it seems to have been done, as this phrase intimates, and to which there is an allusion in (Ezekiel 16:8) . So Jarchi, ``spread the skirt of your garments to cover me with your talith, and this is expressive of marriage;'' and Aben Ezra says, it intimates taking her to him for wife;

though as the word signifies a wing, the allusion may be to the wings of birds spread over their young, to cherish and protect them, which are acts to be done by a man to his wife:

for you are a near kinsman ;
as she had been informed by Naomi, to whom the right of redemption of her husband's estate belonged, and in whom it lay to marry her, and raise up seed to his kinsman, her former husband.