When the love of God, His mercy and forgiveness are understood and God reveals their purpose, it makes sense to share the excitement with others. This is what witnessing is all about -- sharing stories of personal transformation with some detail on how God worked things out. Spoken with love, God's Word accomplishes much.
"So shall My word be that goes forth from My mouth; It shall not return to Me void, but it shall accomplish what I please, and it shall prosper in the thing for which I sent it." (Isaiah 55:11)
In the growth process of a Christian, reading and learning the Bible is foundational. To learn about Jesus Christ, what He did and what He said, read the Gospels of Matthew, Mark, Luke and John. When people ask questions, having Bible verses and Biblical examples fresh in the memory helps communicate the miracles and teachings of Jesus.
"For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart." (Hebrews 4:12)
Ultimately, the goal of witnessing is to preach the Good News to the lost and lead them into the prayer of salvation.
"He who has the Son has life; he who does not have the Son of God does not have life."(1 John 12)
Some people have good arguments about why they don't believe in Jesus or God. Some are confused, or just don't care. Others get uncomfortable or upset when they are confronted with the truth. Therefore, it is important to become skillful at sharing God's Word and offering a personal testimony. When witnessing, people will either choose to listen or they won't. For those who hear, God can begin to use the words as seeds for the soul and to soften their hearts.