‘And Jacob took a stone and set it up for a pillar, and Jacob said to his brothers, “Gather stones.” And they took stones and made a heap, and they ate there by the heap.'
This was clearly acceded to by Laban (Genesis 31:51). It is clear that a stone was set up for each person, one for Jacob and a heap for Laban as the leader, and for the heads of sub-tribes involved in the making of the covenant. Thus Jacob first sets up his pillar to represent his side of the covenant, then the remainder set up stones together in a heap to represent their side of the covenant. We can compare the twelve stones for the twelve tribes in Joshua 4. So there are two silent witnesses to the covenant, the pillar and the heap. As we have seen the setting up of stones was a regular method of having a physical reminder of a covenant (compare Genesis 35:14; 1 Samuel 7:12; Joshua 4:3; see also 2 Samuel 18:18).
“They ate there by the heap.” The eating was a solemn recognition of the peaceful nature of the covenant, as necessary a part of the process as the setting up of the stones. This was probably a ceremonial eating at the setting of the stones, a preliminary to the feast, although it is possible that it simply parallels the feast described later in verse 54, mentioned here as part of the ceremony.