Whether you have been studying your Bible for years or have recently come to Christ, it’s still intimidating to reach the lost. Do you know enough apologetics to defend your faith, as Peter exhorts believers in 1 Peter 3:15?
There will always be many things you and I don’t know. What if a friend lays out evidence that seemingly demolishes your arguments and you don’t know how to rebut it?
First of all, God does not expect us to be experts in everything. Even a PhD chemist is not an expert in paleontology or molecular genetics. But human limitations are not an excuse for laziness. God commands us to grow in grace and knowledge (2 Peter 3:18), to rightly divide the Word of truth (2 Timothy 2:15), and to be wise yet meek (Matthew 10:16 and James 3:13).
That means we need to work at it step by step, faithfully using what we know and continuing to learn. We won’t all attain the same level of skill in apologetics, because we don’t have the same gifts and abilities. But we can all improve as an expression of our commitment to the Lordship of Christ.
As in the rest of life, Scripture must be our first priority in apologetics preparation. Study Scripture and come to know it better and better. Ultimately, the words of God themselves are life (John 6:68) and profitable, equipping us for every good work, including defending our faith (2 Timothy 3:16).
God has also commanded us to observe and study His creation (Proverbs 6:6; 30:18–31). Job 12:7–10, Psalm 19:1, and Romans 1:18–20 tell us that God has revealed Himself in the natural world, so that He is evident to all. The more you learn about science, the easier it is to share the wonders that point to our Creator, Savior, and Lord.
If the Holy Spirit has opened your heart to the gospel, you already know enough to start sharing that good news. God does not need you to be mature to share your faith. As long as your words are consistent with Scripture, even a young believer can be effective. Just one Bible verse and a personal testimony is enough.
So, what if people ask you questions you can’t answer? Don’t be afraid to admit that you don’t know and are still growing. With grace and humility, respond that you would be willing to study the issue and get back to them. Don’t let that distract you. The blind man admitted his ignorance on some things but said compellingly, “One thing I know: that though I was blind, now I see” (John 9:25).
God gives the increase (1 Corinthians 3:7), so your job is to plant and water the gospel seed. Be a good student, learn about the world around you, take time to study arguments that expose the errors of unbelievers, and just “go” (Matthew 28:19). The most important resource is the words of Scripture. Study them and let God’s Spirit use them to pierce the heart of those to whom you witness (John 16:7–11; Hebrews 4:12).
http://www.answersingenesis.org/articles/am/v8/n1/what-to-know