Imagine what it would be like to land on a planet that was inhabited with busy intelligent life! You would be a complete misfit (alien and stranger) to their ways, interests and goals. Such is really a very similar situation for Christians (possessors of eternal life) here on our own planet at the point of initial salvation! In a flash our bodies became inhabited by the Holy Spirit and our spirits were changed by the grace of God. We became aliens and strangers in this same place that was previously our home! Our new HOLY interests and goals are now totally different than they used to be, but we are in a war. Peter wrote:
Dear friends, I urge you, as aliens and strangers in the world, to abstain from sinful desires, which war against your soul. (1 Pet 2:11)
Though radically changed, sinful desires still war against us! We are told in 1 Peter 2:11 and elsewhere that we can successfully resist all temptations (1 Cor. 10:13) and put into practice the word of God (Lk. 8:21).
Furthermore, our citizenship is in heaven (Phil. 3:20) — another reason why we are aliens and strangers here. We are just passing through this uncertain life, which can end at any time and very abruptly. We will leave everything behind when we depart, but we can send treasures ahead! Jesus told his followers (aliens and strangers):
But store up for yourselves treasures in heaven, where moth and rust do not destroy, and where thieves do not break in and steal. For where your treasure is, there your heart will be also. (Mat 6:20,21)
Aliens and strangers (Christians) also long for a better place in a different country:
Christians are just passing through, as holy misfits, in this sinful, strange and hostile world, but we are to think ahead while we live in fear of God (1 Pet. 1:17). [BTW, I do believe in aliens. I am one!] Do you know Jesus? You can’t get eternal life any other way!