Jamieson, Fausset and Brown on Genesis 29:14-20

14-20. he abode a month--Among pastoral people a stranger is freely entertained for three days; on the fourth day he is expected to tell his name and errand; and if he prolongs his stay after that time, he must set his hand to work in some way, as may be agreed upon. A similar rule obtained in Laban's establishment, and the wages for which his nephew engaged to continue in his employment was the hand of Rachel.