Ether 8:15

And it came to pass that thus they did agree with Akish. And Akish did administer unto them the oaths which was given by them of old, who also sought power, which had been handed down even from Cain, who was a murderer from the beginning.

This is how they made their deal with Akish. Akish made them take the same oaths that people took long ago who also wanted power. These oaths had been passed down from Cain, who was a murderer from the beginning.

They made this pact with Akish. Then Akish administered to them the ancient oaths once used by others who sought power—oaths that had been passed down from Cain, who was a murderer from the beginning.