Without considering both testaments, neither can be fully understood in the manner in which God intends them to be understood.
The Mosaic Law is best understood when it is divided into: (1) the moral law, (2) the civil law, and (3) the ceremonial law.
The following is a quote from p42 of Winsome Christianity by Henry Durbanville:
The Book of Numbers is a great book when looking for devotional material. In chapters 1-10 the people seem to be wholly following the commandments of the Lord. However, chapter 11 is the beginning of woes. The very first phrase is "And when the people complained, it displeased the Lord". In chapter 12, we find the murmuring moving up the ranks into the leadership and infecting Miriam and Aaron as they murmur against Moses. In chapter 13, ten of the twelve spies come back with an evil report concerning the land of promise. In chapter 14, we find the people wanting to make a captain to return to Egypt and then wanting to stone Joshua and Caleb for their report of faith. This chapter includes the decision of the Israelites not to go into the land of promise, and then their decision to go into the land of promise after the Lord told them they could no longer go in. The Israelites decide to go against the commandments of the Lord and try to take the land of Canaan on their own, only to be smitten by the Amalekites and Canaanites.
Mathematics can be quite complex, yet one of the most basic divisions of mathematics is called arithmetic. You may better grasp what I am talking about when I say that the most basic operations of arithmetic are addition, subtraction, multiplication, and division. A grasp of these basic operations is a necessity for anyone who desires to grasp any of the more complex divisions of mathematics. Interestingly enough, the same things hold true for the Christian life. It can be quite complex, but at the same time we could break it down to the simplicity of addition, subtraction, multiplication, and division.
In Amos 6:1-6, we find three anchors of hope for the people of Judah. In verses 1-2, we see that they are trusting in the might of their own military. In verse 3, we see that they are trusting in the power of positive thinking, and in verses 4-6 we see that they are resting in their lives of luxury. All of this hope proved to be shallow for Judah, and the same thing holds true for any other nation holding on to these same things.
Inside of your mouth lies one of the most dangerous weapons ever used by mankind. It has destroyed friends, families, churches and peoples. It is such a little member, but it packs a wicked punch. That member is your tongue. It ought to be used to praise the Lord and spread His word, but is most often used to devour others and spread gossip. This member of yours is so dangerous that the Bible likens it to a sharp sword or razor (Psalm 52:2; Psalm 57:4; Psalm 59:7; Psalm 64:3), to a serpent (Psalm 140:3), and to a fire (James 3:5-6). Perhaps we ought to pray like David when he said, "Set a watch, O LORD, before my mouth; keep the door of my lips." (Psalm 141:3).
