'Right Hand' in the Bible

Also, when they perceived that this [special] favor [of preaching to Gentiles] was granted to me, James, Cephas [i.e., Peter] and John, the highly regarded pillars [i.e., leaders of the church] extended to me and Barnabas their right hands [signifying an agreement] to share [in the preaching of the Gospel], with us going to the Gentiles and they going to the circumcised ones [i.e., Jews].