Key features and themes of the Epistles of John include:

1. Themes of Love and Fellowship: John emphasizes the importance of love within the Christian community. The letter repeatedly underscores the commandment to love one another, expressing that God is love and those who abide in love abide in God.

2. Tests of True Faith: The author presents tests by which believers can discern the authenticity of their faith. These include obedience to God's commandments, love for fellow believers, and belief in the truth about Jesus Christ.

3. Christology: John emphasizes the divinity of Jesus Christ. The letter addresses false teachings that downplayed Christ's true nature and affirms Jesus as the Son of God who came in the flesh.

Other features and resources.:

- Background listening allows you to listen to chapters while performing other activities.
- A search mode to easily find chapters.
- Choose between a day mode or dark mode, depending on your mood :)
- An alarm clock feature to start your day off right!
- Filter chapters by theme.
- Easily add your favorite chapters to the favorites list.
- Receive a call while using the app.
- Schedule automatic app shutdown with countdown mode.
- Share a chapter with your friends.
- Compatible with Chromecast and Android Auto.