With a pure and single-minded heart

Luke 20:44 "David therefore calleth him Lord, how is he then his son?"

LUKE 20:41-44

Jesus took an apparent contradiction in scripture and through combining these paradoxical statements (concerning the humanity and deity of Christ) brought forth the truth that Christ is God in human flesh. 
Both assertions (the fact that Jesus was David's son and yet David's Lord) 
were correct and right at the same time.

It was correct that Christ was David's son and it was also correct that Christ was David's Lord. This meant that Christ also was God. However, Christ was not exclusively David's son nor was He exclusively David's Lord. These two truths had to be combined to arrive at the whole truth. No truth of God's Word stands independent of the other truths in God's Word.

A lack of balancing truth with truth is usually the cause of much contention among men when interpreting scriptures. Some argue that everything is by grace, while others emphatically state that without faith it is impossible to please God. The Bible teaches us that we need both grace and faith to be born again - not one without the other. The same is true of faith versus works, and many other truths in God's Word. Error can simply be truth taken to an extreme at the expense of other truths.

One of the concerns of many Christians is, "How can I know I'm thinking and acting properly?" 
If we seek the Lord with a pure heart and singleness of purpose, then the Lord will show us anything we need to change. In other words, all we have to do is focus on the Lord with a pure heart, and He promises to show us any error. 

The only people who need to fear that they might be deceived are those who are not seeking the Lord with a pure and single-minded heart.