"Look to yourselves, that we lose not those things which we have wrought, but that we receive a full reward." (2 John 8)
Let us very clear about this passage. We have no fear of losing our salvation once we believe that Jesus died for our sins and was raised for our justification:
"Seventy weeks are determined upon thy people and upon thy holy city, to finish the transgression, and to make an end of sins, and to make reconciliation for iniquity, and to bring in everlasting righteousness, and to seal up the vision and prophecy, and to anoint the most Holy." (Daniel 9: 24)
"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." (John 3: 16)
"And being made perfect, he became the author of eternal salvation unto all them that obey him." (Hebrews 5: 9)
"Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us." (Hebrews 9: 12)
So, what is John talking about?
He is talking about ignoring or missing out on the unsearchable riches of Christ Jesus:
"Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ:" (Ephesians 1:3)
Paul prayed that the Ephesians Christians, and by extension all believers, would have the following:
"Cease not to give thanks for you, making mention of you in my prayers; 17That the God of our Lord Jesus Christ, the Father of glory, may give unto you the spirit of wisdom and revelation in the knowledge of him: 18The eyes of your understanding being enlightened; that ye may know what is the hope of his calling, and what the riches of the glory of his inheritance in the saints, 19And what is the exceeding greatness of his power to us-ward who believe, according to the working of his mighty power, " (Ephesians 1: 17-19)
We need to have a greater knowledge, awareness, understanding of all that we have received because of Jesus!
We can lose sight of what we have in Christ if we forget who we are, that we are in Christ and that nothing can separate us from Him (Romans 8: 37-39), but also that apart from Him, we can do nothing (John 15: 5)
Don't lose, or rather miss out on what you have in Christ Jesus, but grow in grace and knowledge of Him every day!(2 Peter 3: 18)