There is nothing more important than knowing the truth. For example, say you are traveling somewhere with your family, and you arrive at a fork in the road. There is a man there that seems trustworthy. He speaks to you with kindness and concern, telling you that you must stay left since there have been reports of a band of marauders attacking and killing people on the other road. He tells you to stay left, calls you friend, and assures you all will be fine. The problem is you were just deceived, and in fact there is a killer waiting to ambush you on the road going left.
Jesus warns us in Matthew 24 and emphasized how deception would be rampant in this time where we are now.
Lies have the power to destroy you if you believe them, and live your life based on the lies. So the question as a Christian is how do you know if what you are being taught is 100% the truth? You should not believe half-truths either since they are designed to lead you astray and even more difficult to discern.
Christianity without relationship is religion. Start with loving the truth from your heart and wanting to know the truth. God knows if you love the truth. How do you know what truth is and what is sound doctrine?
The most important point is going to a reliable source. Sometimes others are really telling you what they think and believe. Without learning to read scripture for yourself you won’t ever know. The holy spirit is the real teacher. But before all that, you must have relationship with God through Jesus.
“All this I have spoken while still with you. But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you. Peace I leave with you; my peace I give you. I do not give to you as the world gives. Do not let your hearts be troubled and do not be afraid. -John 14:25
So start with praying for proper discernment, revelation and truth so you are not deceived. God is relational and wants to speak to you. Without relationship you cannot discern what is truth and thereby reject false teaching.
Let God also lead you to reliable sources and warn of false teachers. We all start with listening to pastors whether it is the Christian channel or a local church. My strong recommendation is to start with prominent online pastors such as Joseph Prince, Perry Stone, and Baruch Korman for best results.
Learn to listen to the holy spirit for knowledge and understanding. Meditate as you read and verify if what is being said aligns with the word of God. Read several chapters before a quoted scripture and several chapters after to get CONTEXT. Extremely important to do your truth check. Context is crucial to interpreting scripture correctly and knowing the truth. The bible interprets itself.
For example, someone tells you a Christian has already repented and done with sin since they are now a believer. The problem is if you read in book of revelation where Jesus tells the churches to repent then that does not add up. The truth is Christians will repent after being saved. Paul talks about the struggles with sin in Romans 7. So read all of the new testament yourself and you will be prepared to question false doctrine.
Another false doctrine is if someone tells you the poor go to heaven since Jesus mentions that in the beatitudes. You cannot be a blessing to others when afflicted with poverty. If you are saved by grace alone then your bank account is irrelevant. Are there not poor people that are evil and unrepentant?
Another false doctrine is that salvation is based in part on your efforts concerning works of the law. Salvation cannot be earned since it is a free gift (Ephesians 2:8). The work of salvation has already been done at the cross, so your efforts have no effect. Your part is to firstly believe that, and then strive to live a life of faith and obedience.
You are called to faith and not the law. Your salvation does not give you a license to sin. In fact, as a believer you will resist sin whereas before you did not care. So believe in the salvation you have, repent when you need to, and trust in the Lord. Keep it simple. Jesus Christ and him crucified is the love of God. Often the stumbling block for Christians is believing in their heart that Jesus really loves them and wants a relationship with them as an individual.