9 Then another angel, a third, followed them, crying with a loud voice, “Those who worship the beast and its image, and receive a mark on their foreheads or on their hands, 10 they will also drink the wine of God’s wrath, poured unmixed into the cup of his anger, and they will be tormented with fire and sulfur in the presence of the holy angels and in the presence of the Lamb.
These verses refer back to earlier passages in Revelation where the beast of the sea and the beast from the land force all the people of the world to worship the anti-Christ. They make an image of this false God and compel everyone to worship it and Christians who do not do so are slaughtered.
People are given a mark on their forehead or right hand and cannot conduct business unless they have willingly and with conviction given their allegiance and worship to this false God. Some writers that I have read have stated this mark may not be literal but is symbolic of the willing idolatry of the worshipers of the anti-Christ, though many modern day Christian teachers believe it is a literal mark.
The Expositor's Greek Commentary at biblehub.com, referring to these verses, says, "The third angel proclaims that the deliberate adherents of the Imperial cultus are to be held responsible for their actions, and punished accordingly. The object is that these votaries may be “scared into faith by warning of sin’s pains. The plea of force (Revelation 13:12) is no excuse (cf Matthew 10:28)."
If you want to accept Salvation from Christ here are some resources:
A Prayer for Salvation from Christ:
Lord Jesus, I confess my sins and ask for your forgiveness. Please come into my heart as my Lord and Savior. Take complete control of my life and help me to walk in Your footsteps daily by the power of the Holy Spirit. Thank you Lord for saving me and for answering my prayer.
A more detailed step by step process:
https://www.wikihow.com/Accept-Jesus-Into-Your-Life
