First of all, it's great that your heart is in exactly the right place! You are burdened for your friend’s salvation, and that is truly awesome. God has given you assignment. Let me share with you what Colossians 4:2-6 has to say,
“Devote yourselves to prayer, being watchful and thankful. And pray for us, too, that God may open a door for our message, so that we may proclaim the mystery of Christ, for which I am in chains. Pray that I may proclaim it clearly, as I should. Be wise in the way you act toward outsiders; make the most of every opportunity. Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.”
The first step is prayer. The word “devote” means to commit to something wholly or habitually. Prayer is to be our first and most time consuming priority. Then, we should have others pray also. Do you have a mentor or a Bible study leader, another Bible-reading Christian that you bounce questions off of? This would be an excellent person to help you pray for your father. Drop a card into the prayer ministry at your church, if this is an option for you. Prayer is POWERFUL. Notice Paul mentions it three times in these scriptures.
Next, wait for God to make a way. It's not always good to go in like gangbusters and hound the unbeliever. I read a book today that said, “Changing someone is as easy as making friends with a squirrel by chasing it.” Let God do the work and give you the timing and the words. Sometimes we witness by our lifestyle more than anything.
Finally, get grounded in Biblical truth. Your friend may have questions or challenges one day, and you want to back up your answers with Scripture. Finally, notice the last verse in Colossians 4:2-6 about conversations. Your words should be full of grace, seasoned with salt, so that you may know how to answer. In other words, be giving, respectful, loving as you speak. It is normal for our human emotions to try to take over. Don't give up and trust that God knows what He is doing.
