The place to start simplifying the spiritual life is to make sure you have one.
Jesus frequently challenged the spiritual presumptions of His hearers. He did this constantly with an influential group of men known as the Pharisees. Because of the unusual depth of their interest in and commitment to the things of God (especially Bible study and memorization, prayer, and fasting), they and everyone else were sure that if anyone was right with God, it was these dedicated Pharisees. Jesus once devoted an entire parable to warn against the danger of the spiritual presumption of the Pharisees and people like them (see Luke 18:9-14).
The apostle Paul—who was once a Pharisee himself—likewise warned people about assuming that everything was okay between themselves and God. It was to a group of people who had shown great zeal as followers of Jesus that he wrote, “Examine yourselves as to whether you are in the faith. Prove yourselves” (2 Corinthians 13:5).
Paul once wrote the following to a group of people he himself believed to have spiritual life: “And you He made alive, who were dead in trespasses and sins” (Ephesians 2:1). While physically alive, they had been spiritually dead. But, thanks be to God, “He made alive” by grace through faith in Jesus those who had been spiritually dead. When these people were spiritually dead, they probably thought they were spiritually alive. They would have imagined that they could have gotten as much out of the practices of Christian spirituality as anyone—provided they had any interest in them. And isn’t that what most people think today?
However, the Bible says that until a person is given the Holy Spirit, he “does not receive the things of the Spirit of God, for they are foolishness to him” (1 Corinthians 2:14). No one has spiritual life who does not have the Spirit of God. And only those who know Jesus Christ through repentance and faith have the Spirit of God.
So the reason some feel frustrated about their spirituality is because they’re assuming life and health when in actuality they’re spiritual corpses. Upon what do you base your assurance that the Holy Spirit dwells in you and that you have eternal spiritual life?
Do you know the biblical marks of the presence of the Holy Spirit (as in John 16:8-10, 14 and Galatians 5:22-23) and the signs of God-given spiritual life (as in the letter of 1 John)? Can you see these in your life?
Be sure to verify your spiritual life before you try to simplify it.