Deuteronomy 24:2

And when she is departed out of his house, she may go and be another man's wife.

And when she is departed out of his house,.... With her bill of divorce, by which departure out of his house it is notified to all:

she may go and be other man's wife; it was permitted her to marry another man, she being by her divorce freed from the law of her former husband; and who indeed, in express words contained in the divorce, gave her leave so to do; which ran thus,

"thou art in thine own hand, and hast power over thyself to go and marry any other man whom thou pleasest; and let no man hinder thee in my name, from this day forward and for ever; and, lo, thou art free to any man;''

See Gill on "Matthew 5:31".