1 Corinthians 12:1 (NKJV)
The phrase "ignorance is bliss" is said to refer to someone who is not aware of a problem, and because they are not aware of it, they do not worry about it. While that may be true, ignorance is not really a good thing. Ignorance is defined as a lack of knowledge, education, or awareness. While not knowing something may make it easy not to worry about it, ignorance does not make the problem go away, or solve the problem. Knowledge is better than ignorance, and by having knowledge and understanding about something we are better off.
There are several times in the New Testament where we are told that we should not be ignorant. In 1 Corinthians 12:1, Paul told the Corinthians that they should not be ignorant of spiritual gifts, in 2 Corinthians 2:11, Paul talked about not being ignorant of the schemes of Satan, and in 1 Thessalonians 4:13, Paul told the Thessalonians that he did not want them to be ignorant of the fate of believers who had died. All of these verses show us that God does not want us to be ignorant of biblical things.
If we are ignorant of what God has said about something, then we cannot effectively operate in it. If someone is ignorant of the fact that God's love is in them (Romans 5:5), they may live their life believing they have no control over their emotions and attitudes. If someone is ignorant about what it means to be a new creation and the righteousness of God in Christ (2 Corinthians 5:17, 21), they may live a life below the standard that God has provided for them. Ignorance of God's Word is not bliss, it is dangerous and it can hinder us from living the life God has planned for us to live.