Rabbi Shimon asking Elijah to swear that he will take permission from the Holy one Bless be He, to raise the holy Malchut that fell into exile because the Shechinah and her armies are waiting for Elijah.
Elijah is the keeper of the Covenant (ברית) and Rabbi Shimon is binding him with swear (שבועה) , which is from the root word of seven. A swear is a binding of the lower seven Sefirot to the upper three. It is a power full spiritual force that must be taken seriously. A swear that is not followed create a lot of negativity.
Rabbi Shimon quotes Isaiah 33:7 “Behold, their archangels cry without; angels of peace weep bitterly.” to tell him that the supernal angels are waiting for him to establish the connection of the souls of the Israelites in Malchut with the new Holy Temple.