The mark of the beast is IN the forehead just like the seal of God is IN the forehead. That means in your brain. You either seek God, study His Word and have that sealed in your brain or not. People naturally fear the unknown. God does not need to be unknown. Study His Word to find out about Him and His promises for those who love Him. Many people don't realize that sins sincerely repented for are erased/blotted out and God does not want to hear about them again and He will not bring those up at Judgment Day. For those who love God, Judgment Day is about receiving blessings and the promises He gave for those who love Him.
Revelation 14:9 And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,
2 Timothy 2:15 Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.
Isaiah 45:18 For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited : I am the LORD; and there is none else. 19 I have not spoken in secret, in a dark place of the earth: I said not unto the seed of Jacob, Seek ye me in vain: I the LORD speak righteousness, I declare things that are right.
Luke 8:21 And he answered and said unto them, My mother and my brethren are these which hear the word of God, and do it
Luke 6:45 A good man out of the good treasure of his heart bringeth forth that which is good; and an evil man out of the evil treasure of his heart bringeth forth that which is evil: for of the abundance of the heart his mouth speaketh . 46 And why call ye me, Lord, Lord, and do not the things which I say ? 47 Whosoever cometh to me, and heareth my sayings, and doeth them, I will shew you to whom he is like: 48 He is like a man which built an house, and digged deep , and laid the foundation on a rock: and when the flood arose , the stream beat vehemently upon that house, and could not shake it: for it was founded upon a rock. 49 But he that heareth , and doeth not, is like a man that without a foundation built an house upon the earth; against which the stream did beat vehemently , and immediately it fell ; and the ruin of that house was great.
John 3:14-21 14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up : 15 That whosoever believeth in him should not perish , but have eternal life. 16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish , but have everlasting life. 17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved . 18 He that believeth on him is not condemned : but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God. 19 And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil. 20 For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved . 21 But he that doeth truth cometh to the light, that his deeds may be made manifest , that they are wrought in God.