The eternal life is the life with which the believers are regenerated and which becomes the believers' life (Col. 3:4a), making the believers the children of God (John 1:12-13) and the members of Christ (Eph. 5:30).
In 1 Timothy 6:12 the apostle Paul charged us to lay hold on this eternal life.
The New Testament teaches us that the eternal life has three stages, and these three stages are in three ages—the present age, the church age; the coming age, the kingdom age; and the eternal age, in the new heaven and the new earth with the New Jerusalem as the center. In the first age, the church age, we receive the eternal life. Thus, it becomes our life, and we enjoy this life and live by it. In the church age it is a matter of receiving the eternal life, but in the next age, the age of the kingdom, the eternal life is not for people to receive, but for people to enter into. In Matthew 25:46, those among the nations who are judged by the Lord Jesus to be "sheep" will enter into eternal life in the kingdom age. Thus, in the coming age the eternal life will become a sphere for people to enter into. In that age the eternal life will be given as a reward. In this age the eternal life is for us to receive as a free gift (Rom. 6:23b), but in the coming age the eternal life will be for us to enter into, not as a free gift but as a reward. This reward will be given to both the overcoming believers and to the "sheep" in Matthew 25 who paid a price to take care of Christ's brothers during the great tribulation. Then, in the eternal age, that is, in the new heaven and the new earth with the New Jerusalem as the center, the eternal life will eventually be the consummated gift for all God's redeemed people to manifest the Triune God for eternity.
If we have this view, we will be able to understand a number of verses in the Gospels. In the Gospels the Lord told people both to enter into eternal life and to receive eternal life. In Matthew 19:17 the Lord told the young man to enter into eternal life, but in John, especially in chapter three, He spoke of receiving eternal life. We have received eternal life as a gift, but whether or not we will enter into eternal life as a reward in the future remains to be determined. We may receive the eternal life without doing any work, as a free gift, but to enter into the eternal life requires us to do the proper works, to have the proper virtues, and to pay a price. If we are not clear concerning this, we may feel that the New Testament contradicts itself by saying, on the one hand, that we can receive the eternal life as a free gift, and, on the other hand, that we must pay a price to enter into it. We need to be clear that in the present age, eternal life is a gift given for us to receive, but in the coming age, eternal life will be a reward to recompense us for the price that we have paid for the Lord's sake. Then, in the eternal age, the receiving and the entering will become one.
It is by this eternal life and in this eternal life that the believers have been brought forth. The eternal life is crucial for the producing of the believers and for the building up of the organic Body of Christ.