Reading scripture in context is essential to understanding the Bible. When people misuse or misunderstand Bible verses, it is often because they are reading the verse by itself without considering what was said before and after the verse.
In addition, it is important to understand verses in the context of the entire Bible. The Bible does not contradict itself, yet sometimes people uses verses out-of-context to support opinions that actually oppose the Bible.
The best way to understand this concept is to consider an example.
For example, in John 5:14, Jesus says to a man he has healed, "See, you have been made well! Do not sin any more, so that nothing worse happens to you."
Based on this verse alone, it appears that Jesus is teaching that this man's sickness and tragedy are caused by sin, which is why Jesus tells this man to not sin. However, in this context, Jesus is not really teaching anyone; rather, he is giving this man specific instructions on how to behave now that he has been healed.
Now we need to consider, does Jesus teach about this subject elsewhere?
In John 9:1-3 it says, "As [Jesus] went along, he saw a man blind from birth. His disciples asked him, 'Rabbi, who sinned, this man or his parents, that he was born blind?' [Jesus answered] 'Neither this man nor his parents sinned,' said Jesus, 'but this happened so that the work of God might be displayed in his life.'"
In this context of John 9, his disciples ask him a specific question regarding the connection between sin and illness, to which Jesus responds with a teaching of 'illness is not always caused by sin.'
Furthermore, in Luke 13:2-4 his disciples again ask Jesus a question regarding the connection between suffering and sin, to which Jesus responds, "Do you think that these Galileans were worse sinners than all the other Galileans because they suffered this way? I tell you, no! But unless you repent, you too will all perish. Or those eighteen who died when the tower in Siloam fell on them--do you think they were more guilty than all the others living in Jerusalem? I tell you, no! But unless you repent, you too will all perish."
With these two teachings in John 9 and Luke 13 taken into consideration, we can more clearly see that Jesus is telling this man in John 5 what he has essentially told the people of Jerusalem in Luke 13, "But unless you repent, you too will all perish" or more specifically to this man he has healed 'You have repented; now do not sin anymore so that you do not perish.'
Another example to consider is the book of Job, where a righteous man (Job) experiences tragedy even though he has not sinned.
These are just two of many examples that could be used to illustrate this point that context is essential to understanding meaning. Without context, verses can be used to support almost anything.
The letter of Romans is especially misinterpreted - people use verses in Romans to support beliefs that Paul himself opposes in the same letter!