As Christians, we have been saved by the gospel of Christ (Romans 1:16), and now we have eternal life.  It is not we might someday have eternal life, we already have it.  God has promised us eternal life and He is faithful.  No apostle was clearer on this point than John.  Listen to him:

1 John 2:24-25 (ESV)
²⁴  Let what you heard from the beginning abide in you. If what you heard from the beginning abides in you, then you too will abide in the Son and in the Father. ²⁵  And this is the promise that he made to us—eternal life.  

1 John 5:11-13 (ESV)
¹¹  And this is the testimony, that God gave us eternal life, and this life is in his Son. ¹²  Whoever has the Son has life; whoever does not have the Son of God does not have life. ¹³  I write these things to you who believe in the name of the Son of God that you may know that you have eternal life.

These passages are clear, aren’t they?  They should be a great comfort to all of us who are Christians.  Now, I must point out that this is not teaching the Calvinistic doctrine that says a Christian cannot fall from grace.  If you were reading carefully, you noticed that John set forth a condition that we must meet if we want to maintain eternal life, that is, the Word that we heard, must abide in us (1 John 2:24).  This Word is the gospel.  When it abides in us, we abide in the Son, and this is critical to our salvation.  Jesus tells us that if we do not abide in Him, we cannot bear fruit, and we will be cast into the fire (John 15:5-6).  So, if we are to maintain the eternal life that we were given when we obeyed the gospel, we must continue to be faithful to God (Revelation 2:10).

There is nothing unusual for the promises of God to be conditional.  For example, God promised the Israelites the land of Canaan as a possession.  He told them they would dwell in the land forever (Genesis 17:8).  There was, however, one condition—they had to be true to God (Deuteronomy 30:17-18).  If they were not, they would be expelled from the land even though God promised them it would be theirs forever.  The point is this:  God’s promises are sometimes conditional.  He has promised us eternal life, but, to maintain it, we must be faithful.  We must abide in Christ by allowing His word to abide in us.  If we do this, heaven will be ours and nothing, in or out of this world, can take our eternal life away from us (John 10:27-29).

God has done everything He can to assure that we remain faithful.  He has given us every tool we need to be steadfast in the faith and never lose our salvation (Jude 1:24).  He has given us His Word that guides us through the minefields of life.  He has given us prayer to help us overcome the temptations of the flesh.  He has given us each other to provoke one another to love and good works.  He has given us an advocate, His Son Jesus Christ, who pleads for us in heaven’s court whenever we sin.  No wonder Peter once said we are kept by the power of God (1 Peter 1:1-4).  We have security in Christ.  Our eternal life is intact as long as we want it to be (John 10:27-29).  All we have to do is be faithful.

As you wind down for the night, think about these things.