4 Bible Verses about Political Alliances, By Oaths

So Jonathan made a covenant with the house of David, saying, Let the LORD even require it at the hand of David's enemies. And Jonathan caused David to swear again, because he loved him: for he loved him as he loved his own soul.

Now therefore swear unto me here by God that thou wilt not deal falsely with me, nor with my son, nor with my son's son: but according to the kindness that I have done unto thee, thou shalt do unto me, and to the land wherein thou hast sojourned.

And they said, We saw certainly that the LORD was with thee: and we said, Let there be now an oath betwixt us, even betwixt us and thee, and let us make a covenant with thee; That thou wilt do us no hurt, as we have not touched thee, and as we have done unto thee nothing but good, and have sent thee away in peace: thou art now the blessed of the LORD. And he made them a feast, and they did eat and drink.read more.
And they rose up betimes in the morning, and sware one to another: and Isaac sent them away, and they departed from him in peace.

And Joshua made peace with them, and made a league with them, to let them live: and the princes of the congregation sware unto them. And it came to pass at the end of three days after they had made a league with them, that they heard that they were their neighbours, and that they dwelt among them. And the children of Israel journeyed, and came unto their cities on the third day. Now their cities were Gibeon, and Chephirah, and Beeroth, and Kirjathjearim.read more.
And the children of Israel smote them not, because the princes of the congregation had sworn unto them by the LORD God of Israel. And all the congregation murmured against the princes. But all the princes said unto all the congregation, We have sworn unto them by the LORD God of Israel: now therefore we may not touch them. This we will do to them; we will even let them live, lest wrath be upon us, because of the oath which we sware unto them.