The themes of protection of the widow, the orphan and the poor are central to the moral compass provided by the the Old Testament (Torah).  While scholars busily examine and investigate the origins of biblical myths, they often neglect the origins of biblical motifs and moral imperatives. 

In this case, it turns out that protection of the widow, orphan and the poor are rife throughout the texts and artifacts of the Mid-East Basin.  Richard D. Patterson presents a paper on the subject here:

http://www.martincwiner.com/wp-content/uploads/2010/11/Patterson_Widow_BSac.pdf

Patterson makes mention of a previous paper, that of F. C. Fensham:  “The Widow, Orphan and the Poor in Ancient Near Eastern Legal and Wisdom Literature”.  This paper can be found here:

http://www.martincwiner.com/wp-content/uploads/2010/11/FCFensham-The-Widow-Orphan-and-the-Poor.pdf