Acts 17:2 Then Paul, as his custom was, went in to them, and for three Sabbaths reasoned with them from the Scriptures,
How well do you know your bible? How well do you know the scriptures? Paul was one who had memorised the scriptures and used them every day.
If you know your bible well enough you will be able to reason with people who are stubborn against God, people who believe in other gods and people who know many things in their own religions or beliefs.
God wants us to be able to tell the truth to others and to do that we have to know a certain amount of His word so we can talk to others about it.
Start with one verse and memorise it and all it means.