Sforno on Genesis 20:16/ספורנו על בראשית כ׳:ט״ז

1הנה נתתי אלף כסף לאחיך, as dowry, as was the custom for any groom marrying the daughter or sister of a man.

2הנה לך כסות עינים, clothing consisting of a variety of colours which women used to wear as a mark of distinction. The dowry he gave her brother was intended to show that he did not consider her a whore but someone reputable, and that he did not mean her to be his concubine but his regular wife. Also, he meant that he would not have let Sarah go so easily except for Divine intervention which forced him to let her go.

3לכל אשר אתך, before the eyes of everybody, so that they know in your household that everything is above board.

4ואת כל ונוכחת, and you will be perceived exonerated in every respect even in the eyes of those who would have felt tempted to interpret what happened to you in a negative light, reflecting discredit upon you.