The seal of the living God will be placed upon those only who bear a likeness to Christ in character.
As wax takes the impression of the seal, so the soul is to take the impression of the Spirit of God and retain the image of Christ.
It is obedience to the principles of the commandments of God, that molds the character after the divine similitude.
The seal of God’s law is found in the fourth commandment. This only, of all the ten, brings to view both the name and the title of the Lawgiver. It declares Him to be the Creator of the heavens and the earth, and thus shows His claim to reverence and worship above all others. Aside from this precept, there is nothing in the Decalogue to show by whose authority the law is given.
The Israelites placed over their doors a signature of blood, to show that they were God’s property. So the children of God in this age will bear the signature God has appointed. They will place themselves in harmony with God’s holy law. A mark is placed upon every one of God’s people just as verily as a mark was placed over the doors of the Hebrew dwellings, to preserve the people from the general ruin. God declares, “I gave them my sabbaths, to be a sign between me and them, that they might know that I am the Lord that sanctify them.” Ezekiel 20:12.
Just as soon as the people of God are sealed in their foreheads—it is not any seal or mark that can be seen, but a settling into the truth, both intellectually and spiritually, so they cannot be moved—just as soon as God’s people are sealed and prepared for the shaking, it will come. Indeed, it has begun already; the judgments of God are now upon the land, ... that we may know what is coming. FLB 287
Have a place for secret prayer. Jesus had select places for communion with God, and so should we. We need often to retire to some spot, however humble, where we can be alone with God. Pr 175
And I saw another angel ascending from the east, having the seal of the living God: and he cried with a loud voice to the four angels, to whom it was given to hurt the earth and the sea, Saying, Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads. Revelation 7:2-3 (King James Version)