Specific Text - John 8:30-32
It's impossible to tell if a person is truly your friend until something comes along that tests your relationship. It's easy to be friends when everything is going along smoothly and everyone is having a good time, but it's not until something knocks you down and the other person helps you get back up that you know you've found a true friend.
At this point Jesus was surrounded by "friends" that were just superficial. In chapter 8, Jesus has some pretty brutal words for both His own disciples (v21-29) and the "the Jews who had believed Him" (v30-31). Jesus knew that at this point none of them were true friends, though, because as we know they all would either turn on Him or dessert Him when He was knocked down. Jesus knew that they were still slaves to sin.
So how can you know if you're really a true believer - really a true friend of Jesus - or if you will fade away when the going gets tough? A rough literal translation of v31 helps:
If you remain in my Word, you are a true disciple.
We can understand this a couple of ways. First, you need to keep doing what you're doing right now: reading God's Word. Keep reading it, and keep doing what it says and you will be a true disciple. Secondly, remember what you memorized in John 1 - In the beginning was the Word, and the Word was with God, and the Word was God. Jesus is the Word, so not only must you keep reading the Bible, but you must remain in Him. Participating in the Spiritual Disciplines we are learning about this summer will help you do this.
Remember, this is something you must do, and keep doing, but you don't do it on your own. The Holy Spirit continually provides you with this strength and ability, and ultimately these disciplines will free you from your slavery to sin:
When you know this truth, the truth will free you. (v32)
Do you see how this process works? The more you work on your Spiritual Disciplines (by the Holy Spirit's power), the more you will know the truth, and the more you will be set free from sin!
Prayer For The Day - Dear Father in Heaven; I want to be a true believer. Thank you for kindling a love for you in me, and thank you for giving me strength to build up my belief for you. Help me to remain in your Word forever. Amen.