4 Bible Verses about Political Alliances, By Oaths

So Jonathan made a covenant with the house of David, saying, "Yahweh will require it at the hand of David's enemies." Jonathan caused David to swear again, for the love that he had to him; for he loved him as he loved his own soul.

Now, therefore, swear to me here by God that you will not deal falsely with me, nor with my son, nor with my son's son. But according to the kindness that I have done to you, you shall do to me, and to the land in which you have lived as a foreigner."

They said, "We saw plainly that Yahweh was with you. We said, 'Let there now be an oath between us, even between us and you, and let us make a covenant with you, that you will do us no harm, as we have not touched you, and as we have done to you nothing but good, and have sent you away in peace.' You are now the blessed of Yahweh." He made them a feast, and they ate and drank.read more.
They rose up some time in the morning, and swore one to another. Isaac sent them away, and they departed from him in peace.

Joshua made peace with them, and made a covenant with them, to let them live. The princes of the congregation swore to them. It happened at the end of three days after they had made a covenant with them, that they heard that they were their neighbors, and that they lived among them. The children of Israel traveled and came to their cities on the third day. Now their cities were Gibeon, Chephirah, Beeroth, and Kiriath Jearim.read more.
The children of Israel didn't strike them, because the princes of the congregation had sworn to them by Yahweh, the God of Israel. All the congregation murmured against the princes. But all the princes said to all the congregation, "We have sworn to them by Yahweh, the God of Israel: now therefore we may not touch them. This we will do to them, and let them live; lest wrath be on us, because of the oath which we swore to them."