We know the custom of laying the foundation stone of a building or a house. Laying such a first stone is important and is often accompanied by a ceremony. But how do we come up with such a custom, does it have an origin? I think so, because in the Bible you read:
Genesis 31
45 And Jacob took a stone and set it up for a monument.
46 And Jacob said to his brethren, Take up stones. And they take stones and make a heap of stones. And they ate there in the heap.
the first stone
Jacob takes a stone and sets it up as a memorial stone or a pillar. The stone is a picture of Christ in Scripture (Ps.118:22, Acts4:11; 1 Cor.10:4). Despised (rejected and killed) by the people and their leaders, but raised up by God.
Christ
Christ is the firstfruits who was raised from the dead (1 Cor. 15:20, 23) and is the first stone set up. That indicates ranking, but He is also the First in order. The ecclesia is a spiritual mansion, a spiritual temple, and Christ Jesus is the Cornerstone of this structure, upon which the ecclesia is built and the whole building is interconnected (Eph. 2:20-21). He is the First in all and everything (Col.1:18).
the other stones
The other stones in the building of Jacob and Laban are therefore a representation of the house of God, the ecclesia, of which Jesus Christ is the most important stone (Eph.2:19-22). The passage in Ephesians 2 also describes that God has made Jew and Gentile one in Christ (Eph.2:14).
That is what Jacob, as an image of Israel, and Laban (a Syrian, see Gen.25:20) portray by eating together on this heap. A meal is a picture of fellowship and unity (1 Cor. 10:16). The fact that the cairn is subsequently called Mizpah, which means watchtower, a place with a view, is a nice confirmation (Col. 1:9; 2:2).