This is what God gave me today in His word:
Keep back your servant also from presumptuous sins; let them not have dominion over me! Then I shall be blameless, and innocent of great transgression. Let the words of my mouth and the meditation of my heart be acceptable in your sight, O LORD, my rock and my redeemer. (Psalms 19:13-14)
I love passages like this, because, even though they’re in the Old Testament, they teach something from the New Testament. For example, in the first verse David is crying out to the Lord, and asking that God would keep him from being dominated by sin. Essentially, David does ask God to keep him from sin, but he specifically asks that God would keep him from being dominated by sin. David knows that he’ll sin, but he’s asking that God would keep sin from dominating his life. This a concept (i.e., that even as Christians we will still sometimes fall to sin, but that God can and will keep it from dominating our lives) that is taught in the New Testament as well… In fact, we can see it in various different passages, for example:
No temptation has overtaken you except what is common to mankind. And God is faithful; he will not let you be tempted beyond what you can bear. But when you are tempted, he will also provide a way out so that you can endure it. (1 Corinthians 10:13)
Likewise, in the second verse David is asking God to let his words and meditation be acceptable before God. Now, this particular bit is actually teaching more through contrast with the New Testament then through comparison… By that, I mean that in the New Testament we see that, if we are Christians, our words and what we meditate on are (or at least should be… Naturally, as mentioned earlier, we will stumble) acceptable to God.
In conclusion though: We can see New Testament truths and events all throughout the Old Testament… In small things, such as the two bits of teaching that were mentioned, and in big things. The ‘biggest’ thing of all, that we see constantly being foreshadowed all throughout the Old Testament, is the Gospel. We see it foreshadowed in Abraham, when he is told to offer his son Isaac as a sacrifice. We see it foreshadowed also with Joseph, who, to keep the people from starving, was betrayed into the hands of evil men, only to then be exalted to the right hand of Pharaoh… In short, almost every passage in the Old Testament points forward, or elaborates upon, something in the New Testament… The two testaments aren’t meant to be read separately, but rather to explain various things in one Testament or the other.