In Deuteronomy 30, God, through Moses, says that the choice to keep His commandments, his law, is to choose life.
On the other hand, Paul calls the giving of that same law, those same commandments “the ministration of death” (2 Corinthians 3). He links the law again with death when he says “Death’s sting is sin and sin’s strength comes from the law” (1 Corinthians 15). For all intents and purposes, the law brings death, whether or not he gives it lip service by saying the law is good. In the very same place he gives this lip service, a verse after, Paul says sin used the God’s commandment to kill him because the law in incompatible with his nature. You don’t believe me? Read and understand.
“… the law [is] holy, and the commandment holy, and just, and good. Did that which is good become death to me? May it not be so! [or, translated as “God forbid!”] But sin, so that it might appear sin, resulting in death to me by that which is good; so that sin might become exceedingly sinful by commandment. For we know that the law is spiritual: but I am fleshy, sold under sin.” (Romans 7:12-14)
Don’t let Paul’s pretense with “God forbid!” fool you. Just understand what he is actually saying. He says that the law is good and righteous, BUT sin results in death by “that which is good”, i.e., the law. Essentially, sin uses the law to kill people. The commandment makes sin more evil! And the law is “spiritual” whereas Paul is fleshy. In the christian worldview, that’s an incompatibility, what is fleshy and what is spiritual.
With this mindset, see what God is saying to Israel when he gives them a choice. When he says “choose life and keep the commandments”, in the Pauline world, it’s like saying “choose life, and be killed by sin.” That’s me being blunt. Think about it. According to christians, no one can keep the commandments because their god demands perfection. And Paul adds his bit with sin using the law and commandment to kill people because his view of the law is only spiritual whereas people are just fleshy. So we essentially have God saying “choose life and die”.
So we have God saying obedience to his law actually gives life and Paul and his acolytes saying the law brings death. And out of a choice between God and a man, once again, christians choose man.
But in this case, they essentially call God a liar: to them, God said law brings life when, in real life, it brings death.