You do not need to know everything about the Bible, biblical doctrine, or the gospel before sharing your faith with others.
John the Baptist did not have an exhaustive knowledge of the gospel. Yet, God used him powerfully to minister to others with the truth he possessed. Jesus even said of him, “Among those born of women, there has not risen anyone greater than John the Baptist” (Matthew 11:11).
As born-again believers, we all possess enough biblical truth to adequately explain the gospel because we have experienced salvation ourselves. At the very least, we can tell others how and why we trusted Jesus by faith and what resulted from that vital decision.
We must also never underestimate the Holy Spirit’s ability to use our words to convict others of their sins and convince them that they need salvation. If He did it for John the Baptist when he shared God’s truth, He could do it for us. Remember, God is the same yesterday, today, and forever (see Hebrews 13:8).
Have you been letting your lack of exhaustive Bible knowledge or fear keep you from sharing your faith in the past? If so, I encourage you to trust the Holy Spirit to use what you already know and “Go for it!”