Thank you for the question on sharing the Gospel of Christ, “Is an hour long enough to hear the full gospel of Christ?”
The Apostle Paul defines the core of the Gospel of Salvation in I Corinthians 15:1–8. I cite the passage: “Now, brothers and sisters, I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand. 2 By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.
3 For what I received I passed on to you as of first importance[a]: that Christ died for our sins according to the Scriptures, 4 that he was buried, that he was raised on the third day according to the Scriptures, 5 and that he appeared to Cephas,[b] and then to the Twelve. 6 After that, he appeared to more than five hundred of the brothers and sisters at the same time, most of whom are still living, though some have fallen asleep. 7 Then he appeared to James, then to all the apostles, 8 and last of all he appeared to me also, as to one abnormally born” (A searchable online Bible in over 150 versions and 50 Languages).
Perhaps I may be reading into the question, but the adjective, full, before the noun Gospel causes me to be skeptical. What do I mean by this? It give the perception that one is “forcing” the person to listen when that person doesn’t want to hear any more. It also may give the impression that one hour is not enough time to share the full Gospel. Sharing the “full” Gospel does not mean that one has to delve into imputed sin of Adam and Eve, total depravity of humans, double predestination, the Kenosis Theory on the nature of Jesus Christ, etc. That person would not know what one is speaking about. An hour is not enough for seminaries have a semester on Soteriology for a broad framework on that topic.
The key focus is on the core of the Gospel as the Apostle Paul stated in I Cor. 15. Facts do not ensure that a person will believe by faith in the work of Jesus Christ in atoning for one’s sins. There are many atheists who know the “full” Gospel and yet they do not believe it. Salvation is the work of the Holy Spirit, not of Christians. Christians are to be witnesses to those who are willing to listen. More often than not, a person who comes to faith in Jesus Christ has been prayed for by others whereby the seed has been sown, others has water it, and others have the privilege of seeing that person come to faith. To presuppose that one can share the “full” Gospel in one hour is faulty thinking. It is better to have a simple discussion on one’s need of God or for the Savior. The natural flow over time will lead to the consideration of the God who loves him or her and how that love of God has been shown to him/her. “But God demonstrated his love toward us in that while we were still sinners, Christ died for us” (Romans 5:8). It is a step by step process for someone to come to know Jesus Christ as one’s own Savior and Lord.
SUMMARY: Facts do not save a person, but faith in Jesus Christ in his atoning work for one’s own evil attitude and actions.
For more perspectives:
https://www.quora.com/Is-an-hour-long-enough-to-hear-the-full-gospel-of-Christ