This is a good article about why it is important to study the Old Testament and not just the New Testament. I recently read through several Old Testament books and learned so much about the character of God and how He really is the same today as then.
Why Study the Old Testament? (from GotQuestions.org)
There are many reasons to study the Old Testament. For one, the Old
Testament lays the foundation for the teachings and events found in the
New Testament. The Bible is a progressive revelation. If you skip the
first half of any good book and try to finish it, you will have a hard
time understanding the characters, the plot, and the ending. In the same
way, the New Testament is only completely understood when we see its
foundation of the events, characters, laws, sacrificial system,
covenants, and promises of the Old Testament.
If we only had the New Testament, we would come to the Gospels and not
know why the Jews were looking for a Messiah (a Savior King). We would
not understand why this Messiah was coming (see Isaiah 53), and we would
not have been able to identify Jesus of Nazareth as the Messiah through
the many detailed prophecies that were given concerning Him [e.g., His
birth place (Micah 5:2), His manner of death (Psalm 22, especially
verses 1, 7–8, 14–18; 69:21), His resurrection (Psalm 16:10), and many
more details of His ministry (Isaiah 9:2; 52:3)].
A study of the Old Testament is also important for understanding the
Jewish customs mentioned in passing in the New Testament. We would not
understand the way the Pharisees had perverted God’s law by adding their
own traditions to it, or why Jesus was so upset as He cleansed the
temple courtyard, or where Jesus got the words He used in His many
replies to adversaries.
The Old Testament records numerous detailed prophecies that could only
have come true if the Bible is God’s Word, not man’s (e.g., Daniel 7 and
the following chapters). Daniel’s prophecies give specific details
about the rise and fall of nations. These prophecies are so accurate, in
fact, that skeptics choose to believe they were written after the fact.
We should study the Old Testament because of the countless lessons it
contains for us. By observing the lives of the characters of the Old
Testament, we find guidance for our own lives. We are exhorted to trust
God no matter what (Daniel 3). We learn to stand firm in our convictions
(Daniel 1) and to await the reward of faithfulness (Daniel 6). We learn
it is best to confess sin early and sincerely instead of shifting blame
(1 Samuel 15). We learn not to toy with sin, because it will find us
out (Judges 13—16). We learn that our sin has consequences not only for
ourselves but for our loved ones (Genesis 3) and, conversely, that our
good behavior has rewards for us and those around us (Exodus 20:5–6).
A study of the Old Testament also helps us understand prophecy. The Old
Testament contains many promises that God will yet fulfill for the
Jewish nation. The Old Testament reveals such things as the length of
the Tribulation, how Christ’s future 1,000-year reign fulfills His
promises to the Jews, and how the conclusion of the Bible ties up the
loose ends that were unraveled in the beginning of time.
In summary, the Old Testament allows us to learn how to love and serve
God, and it reveals more about God’s character. It shows through
repeatedly fulfilled prophecy why the Bible is unique among holy
books—it alone is able to demonstrate that it is what it claims to be:
the inspired Word of God. In short, if you have not yet ventured into
the pages of the Old Testament, you are missing much that God has
available for you.
Does anything else replace God in your heart?
“Do not let your heart turn to her ways or stray into her paths. Many are the victims she has brought down; her slain are a mighty throng. Her house is a highway to the grave, leading down to the chambers of death.” Proverbs 7:25-27 NIV
The “her” spoken of in Proverbs 7 is a worldly adulteress actively seeking to lead her victims astray. For Christians, adultery against the Lord is anything our hearts becomes entangled with, anything that replaces our desire for him.
The Bible is full of examples of those who were brought down by things they desired more than God. It began with Adam and Eve, who chose to listen to the enticing lies of Satan instead of what God promised. Esau gave up his inheritance for a bowl of stew. The children of Israel repeatedly rebelled and chose other gods over Yahweh. In so doing, they broke their promise to be faithful only to him. Sometimes the sin was literal adultery, as with David and Bathsheba. In each case the result was the same: separation from God with dire consequences.
The Bible often refers to the relationship between the body of Christ and the Lord in terms of a marriage. The vows of marriage represent a covenant – a promise to be exclusively faithful to each other. When we trade our affection for Jesus for what the world has to offer, we break that promise. Yet, amazingly, he remains faithful to us no matter how much we break his heart. 2 Timothy 2:13 says even when we are faithless, he remains faithful because he cannot deny himself.
Scripture tells us God is a jealous God (Exodus 34:14, Deuteronomy 4:23-24) but this isn’t the kind of negative jealousy we think of, that controls or seeks revenge. The word also means “zealous”. His love for us is one of zealous vigilance that will pursue us and do whatever is necessary to protect our covenant relationship with him. He demonstrated the depth of his love by dying on the cross for us and securing the promise of eternal life.
Our heavenly Father says in Jeremiah 31:3, “I have loved you with an everlasting love; therefore I have continued my faithfulness to you.” Take time today to express your love to the Lord and thank him for his zealous faithfulness.