I'll ask you to do your own research, there's a lot to cover, but if you word search "seal of God" in the Bible, you will find scripture after scripture about how God knows them that are His, like 2 Timothy 2:19 Nevertheless the foundation of God standeth sure, And having this seal, the Lord knoweth them that are his. And, Let every one that nameth the name of Christ depart from iniquity.
Revelation 6:9
And when he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held: And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth?
Revelation 7:2,3
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 9:1-4
And the fifth angel sounded,...vs 3 And there came out of the smoke locusts upon the earth: and unto them was given power, as the scorpions of the earth have power. vs 4 And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads....
Herein is our encouragement, that when we accept Christ as our Savior, repenting of our sins, with His forgiveness, and follow Him unto the end (why WOULDN'T we follow Him unto the end; is there anything BETTER??), we have the seal of God and are His forever.
The apostles, book of Acts Christians, Christians throughout all of time, have been tormented, killed, tortured,..HOWEVER, we will all die SOME day, so whatever we do go through, if we have the seal of God IN our foreheads, we cry out to Him, we sing songs of thanksgiving unto Him, we TRUST in Him,....
Zechariah 4:6
...Not by might, nor by power, but by my spirit, saith the Lord of hosts.
I wanted to learn about all of the provisions God provided for the Isrealites after they left Egypt. I googled Provision from God in the Wilderness, up it popped, so I clicked on that and in learnthebible.org there was everything I needed to know, including definitions of words, and scripture searches. Extremely helpful to me. Do your own research so that you will be strong in the Word for yourself.
John 15:4-7
Abide in me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; no more can ye, except ye abide in me. I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing. If a man abide not in me, he is cast forth as a branch, and is withered; and men gather them, and cast them into the fire, and they are burned. If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you.
I know from my own experience, when I don't remain in the word daily, or get side tracked by doing other things on a regular basis, don't hear the word, not pray for long periods of time, I feel like I wither, shrivel up, have nothing that comes to my aid when I need it, spiritually speaking, as well. We can't depend on other people to pull us through all of our troubles, or help us every time we have a need; but we CAN count on the Lord to provide. One day I'll tell y'all about how the Lord provided for me/us on many occasions, when He was the only one that knew about the need. Fascinating!