Study Deuteronomy

Jesus knew Deuteronomy very well. In the three temptations recorded in Matthew and Luke, he simply quoted passages from Deuteronomy to counter Satan. Therefore, if Christians are true to their master, they should study Deuteronomy as well.
Modern people take it for granted that as citizens of a country, it is their responsibility to know the law. Of course, if one leads a moral life, there is no need for him to know the letters of the law because his life follows naturally. If you know the law, you are able to protect your interests. You have law-enforcers to protect your life and property. Of course, people may abuse the law for their advantage. For example, the recent speeding case of a Hong Kong tycoon, Mr. Lxxxx.
In ancient times, common people were not allowed to know the law. Only nobles and aristocrats knew. Moreover, laws were subject to the whims of kings. Therefore, we would expect a lot of injustice happening around. In ancient China, 536 B.C., it was revolutionary for 子產 to inscribe the laws on bronze tripods to make them known to all the people【左傳‧魯昭公六年】. At first, the nobles complained. Two decades later, other warring states followed suit【左傳‧魯昭公廿九年】. Confucius 孔子 lamented the situation because all people, nobilities as well as commoners, had become equal before the law. Then, people would not know their distinct status in a country. This country would soon collapse.

In sharp contrast, Deuteronomy 4 opens a window for us to take a glimpse of how the Israelites saw themselves. Yahweh entered into a covenant with them. They had to keep all the statues and ordinances taught by Moses, God's representative. Instead of seeing them as restrictive, the Israelites were proud of these statues and ordinances instead. There were no nobilities worrying about making known the laws to the commoners. There were no political philosophers lamenting for a confusion of roles and status, leading to the collapse of a country.
Keep them and do them; for that will be your wisdom and your understanding in the sight of the peoples, who, when they hear all these statutes, will say, 'Surely this great nation is a wise and understanding people.'
For what great nation is there that has a god so near to it as the LORD our God is to us, whenever we call upon him?
And what great nation is there, that has statutes and ordinances so righteous as all this law which I set before you this day? (Deuteronomy 4:6-8)
These statues and ordinances are righteous because they were given by God. They were guidelines to help the Israelites lead a holy life (Exodus 19:6).
Thy word is a lamp to my feet and a light to my path.נֵר-לְרַגְלִי דְבָרֶךָ;    וְאוֹר, לִנְתִיבָתִי  (Psalm 119:105)
Therefore, keeping them is wisdom and understanding in the sight of the nations. Even Jesus affirmed their importance.
Think not that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfil them (Matthew 5:17). Therefore, it is foolish for Christians to disregard them.

My God, Your wisdom is beyond comprehension. For Your loving care, You gave the Israelites the Torah to lead a holy life and pass on this wisdom to mankind. May we study them diligently, love them with all our heart and live them up. We are feeble and insignificant. Strengthen us so that we may lead a life pleasing and acceptable to You. Amen.