For to me to live [is] Christ, and to die [is] gain.
Note 12 at Php 1:21: What is life all about? What is the purpose of one's existence? What is to be gained in life? What do people live for? Paul answered these questions by saying that the process of life and continuous living is only to be found in Christ. Paul indicated that true life is only to be found in Christ. It is not to be found in prestige, fortune, fame, or things, but only in the one who is life--Jesus Christ (Joh 14:6; 1Jo 1:1-2, 5:12, and 20). This life is a quality of life, not a quantity of time. God has given us eternal life, and this life is in His Son (1Jo 5:11).
When we say so-and-so is "my life," we mean that all of our attention is given to, our focus is directed toward, and our purpose in living revolves around that person. In a similar way, Paul's sole purpose was to be totally consumed with Christ and His life. To Paul, life was Christ. We should have the same attitude.
Note 13 at Php 1:21: The word "gain" means to advance or progress. Many people do not have this perspective that death is better than life. Those who are not born again go directly into eternal torment (see note 4 at Mr 3:29 and note 13 at Mt 5:22), but for those who are born again (see note 2 at Joh 3:3), death is the doorway that brings them into the very presence of God. Death is promotion for the saint.
Fear of death causes people to compromise their convictions and brings them into bondage (Heb 2:15). Understanding that death ushers the believer into an existence that is infinitely better than life here on earth breaks all fear and allows believers to act as instructed by the Lord, regardless of the consequences. Death is not the end; it is just the beginning for those who put their faith in Christ.