Note from A. Frances Werner:

In this wonderful passage regarding the messenger stopping Abraham from sacrificing Isaac, there is an interesting Hebrew word (Y'CHID, Strong's number 3173) which is usually translated "only" or "beloved" with the addition of the word "son".  However, there is only a single word in the ancient language, showing the incredible value of an solitary offspring both to parents and to God. 

This word also occurs with the exact same spelling in the Aramaic New Testament.  A surprising number of the healings done by Yeshua (Jesus) are for the "only-child" of a distraught parent.  The New Testament also clearly ties this word to Yeshua himself.