Chapter 1 warns to not believe in false idols or teachings and associate with people who do not believe in the word of God. John is stressing the need for love and respect among those who call themselves a Christian. There will be many people in the world that will try and deceive you of false teachings, don't fall for it! Those who do not follow the commandments are not even really followers of God. John said to be cautious around false teachers. If someone preaches directly from the word is not a false teacher. Those who understand and take in the word should know right from wrong teachings. The word of God must be protected and preached to the people who wish to hear the word. If you let the devil enter your life it is hard to get rid of it because of temptation. There are things that are tempting in this world but we are not to fall into that trap. That's why Jesus is there for us, all we need to do is have have faith and trust in the Lord. Christians must guard and protect everything that pertains or is related to Jesus. Because Christanity was under attack.
Like the the Word of God must be protected love how you said that, we are to protected it in a variety of ways but sharing it and keeping it true and real and also by storing it in our hearts.
We are reminded to love one another and that this has been the same from the beginning. This is not of me but my bible: the way John approaches this is by first commended them by giving them some price and edifying them, then exhorts them to help communicate the true of what is going on and to help them out, then explaining that will help establish the truth and build relationships. A great example of how to communicate and talk to people. We must remain on guard about the truth and can't take it for anything. Doing so we must first establish the relationship ourselves and know the Word and what we believe good enough to not believe them. Even if they look good or are a pastor or leader or anything just because of this doesn't mean its always right. May look good and have the position but doesn't mean what they are telling you is the truth. Just love the last part too- think shared one time (maybe on our trip) that some times a letter (now days a text or message or something snap chat.... list goes on is okay) but the real communication should be in person.
I like what both of you said, Do not have anything to do with false teachings they will infect your mind and are hard to get out. The true test of who can be trusted is if what the say lines up with what God says in the Bible.
This is really a good example of how we should communicate with people John had built a relationship with with this person and they both knew they could trust each other. He also knew that face to face is always better it is easier to understand what the person is truly thinking.