4 Bible Verses about Political Alliances, By Oaths

So Jonathan made a covenant with the house of David. And Jonathan swore unto David 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 mercy that I have done unto thee, thou shalt do unto me and to the land in which thou hast sojourned.

And they said, We have seen certainly that the LORD is with thee; and we said, Let there be now an oath between us, even between 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 banquet, and they ate and drank.read more.
And they rose up early in the morning and swore one to another; and Isaac sent them away, and they departed from him in peace.

And Joshua made peace with them and made a covenant with them, to let them live; also the princes of the congregation swore unto them. At the end of three days after they had made a covenant with them, they heard how they were their neighbours and that they dwelt among them. And the sons 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 sons of Israel did not smite them 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; therefore, now we may not touch them. This we will do to them; we will let them live lest wrath come upon us because of the oath which we swore unto them.