It might be tempting to think we can cut the New off from the Old but it doesn't work that way. St. Augustine wrote, "The New Testament is hidden in the Old and the Old is made manifest in the New." They form a unit of God's loving care for us.
The Old is read at Mass to show this unity and the unity of the history of salvation - a unity that has Christ in the Paschal mystery as its centre.
The Old Testament is really a love story between God and the people of Israel. These were Jesus' people. He lived the Old Testament and it nourished him. He referred to it and quoted it frequently during his ministry.
Those who wrote the New certainly knew the Old Testament well. If we don't know the Old Testament, the New is impossible to understand. Therefore, the Church wants the Old Testament read at Mass to stimulate us to read and study it at other times.
We have problems with understanding the Old Testament because it comes from an ancient culture and we tend to be biased against the Old.
The battles and killings deter us, but we need to understand that they reveal how the Israelites saw God's hand in every event, even though they may not be historically accurate in their details. In addition, hard to pronounce and hard to-keep-track-of names make reading difficult.
LACK OF CONTEXT
Another obstacle is the short segment read at Mass without any reference to context. So, we fail to understand the point of the story. It's like being told the punch line of a joke without the whole story or coming in at the middle of a movie and trying to guess what's going on.
Here is an example from 2 Kings 5. This story of 27 verses, full of suspense and humour, is so dramatic that it should be acted out. But all we hear at Mass are four verses that tell of Naaman's healing and his request for some of Israel's soil.
Of course, reading the whole story would be too long but if we really knew the OT, the short reading would bring to mind this valuable incident.
The story tells us Naaman, the great army commander of Syria, suffers from leprosy. An Israelite slave tells him of a prophet in Samaria who could cure him.
Naaman, his chariot loaded with precious metals (10 talents of silver, 6000 shekels) and 10 festal garments, carries a letter from his king asking Israel's king to cure Naaman. In a dramatic reaction to the letter, the king tears his garments, suspecting a nasty trick.
ACT ON FAITH
The prophet Elisha asks for the man. When Naaman arrives, Elisha sends a messenger to tell him to bathe in the Jordan seven times and he will be cured.
Naaman, expecting a much better welcome from Elisha, is insulted and angry. Only at the pleading of his servants does Naaman follow Elisha's instructions and he finds himself cured.
Naaman then goes back and tells Elisha that he realizes Israel's God is the only true God whom he will worship henceforth. He begs Elisha to accept his gifts. Elisha refuses. But the story doesn't end there. I suggest you read the entire story and watch for it in the Sunday readings.
Paired with this is Luke's Gospel story of the healing of 10 lepers by Jesus. Jesus heals 10, so obviously Jesus is more powerful than the Old Testament prophets.
LEPER GIVES THANKS
Only one leper returns to thank Jesus, a Samaritan, an outsider like Naaman. What a contrast with the foreigner Naaman and his acceptance of Israel's God and the nine Israelite lepers who fail to acknowledge Jesus' power or even thank him.
There is great value and beauty in the Old Testament. Vatican II in its Constitution on Divine Revelation said it "remains permanently valuable" and its books "give expression to a lively sense of God, contain a store of sublime teachings about God, sound wisdom about human life, and a wonderful treasury of prayers, and in them the mystery of our salvation is presented in a hidden way. Christians should receive them with reverence."