We must always begin with the Bible: “What sayeth the Lord?”
I Peter 3:15: Notice with me, first, what Peter actually says: “…Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. …”
Peter says we should be prepared, be willing to provide answers to folks who are inquiring.
This is so freeing for it means we don’t have to “go after” people; rather, we simply answer and/or get answers for people who genuinely have questions. After all, Jesus didn’t stage any debates with His critics — He simply answered them, refuting the charges they initiated!
Jude 3: Jude, on the other hand, urges the saints to staunchly defend (epagonizomai), vigorously fight for and protect the faith handed down to them by the Apostles. This fight was against false brethren (Gnostics), apostates who had covertly joined their fellowship, pretending to be brothers in Christ, but who in actuality were introducing false doctrine into Christ’s church.
The truth, the purity of the Gospel was at risk! These men and their doctrinal poison had to be exposed and rejected!
It’s important to note that these were men who had infiltrated the church. Our “fight” is for the purity of God’s Word; we are to preserve it; we are to teach it in our local assemblies. Jude says nothing about striving or fighting against the world, or even false religions “out there.” Jude’s concern was to keep corrupting, compromising doctrinal influences out of the church.
ELECTION: Next, we must take into account passages such as John 6:44 where Jesus quite plainly and clearly teaches that no one can believe in Him unless God the Father first draws or calls that person. This “drawing” is closely related to the doctrines of Election and Predestination (e.g., Romans 8:27-30; 9; Ephesians 1). Simply put: God first initiates work in a person’s heart so that they are interested and enabled to respond to an invitation to receive Christ.
REBELLION: Some folks, upon hearing the gospel along with understanding the moral expectations placed upon them, should they respond, simply count the cost then say “No thanks!”
GIFTING: Undoubtedly there are both men and women gifted of God with a facility for debating, for defending, for clearly and logically explaining the truths of our faith — men and women such as Apollos (Acts 18:24-28). Such folks can be powerful instruments in the hands of Almighty God!
That we are called to share our faith is quite clear in the Bible, but bear in mind this basic maxim: Witnessing is simply sharing the gospel, in the power of the Holy Spirit, and leaving the results up to God!