Why did Nadab and Abihu Offer Strange Fire?

What were Nadab and Abihu thinking? Why would sons of the high priest offer strange fire unto the LORD? Were they drunk? Were they following their father's example? In this lesson, we will look at their possible mindset during this time and why what they did was sinful.
We will also be looking at Luke's gospel account and some of the important things found in it.