Seal in 1King21:8 " Sealed[letter], with his Seal." is one type of Seal where a signet, or signet ring was employed. The other Seal is for the Election/Chosen ones of our LORD: and it is based off of Faith - in the LORD. Fake-ones need not apply[2Tim.2:19].
The 7 Seals of Revelation are both of the above. The LORD's People have been Sealed. The process is well under-way; we are at the Fifth  Seal. The information is being revealed by peeling back the layers of onion skin: one layer fulfills it's purpose and become stale or cloudy, then it is time to peel off the next layer.
Without faith, it is impossible to please the LORD. Without faith, people can only see the manifestation of a noun. People without faith, can Not be trusted. *Newsflash* - the first two[6,6] of the three[6,6,6.] sixes are already present on the earth. First 6 = Rev.6:12:Seals.
Second 6 =Rev.16:12: Vials. The kings of the east are terrorist, armed with weapons from Atheist nations, crossing the river as if it were not there: headed to the Middle, then Western world. Their crowns are made of cloth. Life matters not, without Immanuel-Christ-Jesus.
The Creator of heaven and earth, came to earth to Save mankind. If man could Save ourselves, Christ would not have had to do it. Salvation is for the individual, it is personal, and open to all that are born of woman, in this earth age.
Do not follow Unbelievers; period.