Why did God not just give us some commands to g by like the 10 commandments so that we would know if we were doing his will?
God, in his infinite wisdom (Isaiah 55:8-9), wrote the Bible as he saw fit. What men often think is too difficult and makes no sense at all, makes perfect sense when “rightly divided.” The Bible “fits like a glove” when handled correctly. Every part of it matches with every other part. There are no contradictions. Man is the author of confusion, not God (1 Corinthians 14:33). Man makes the Bible difficult by not searching the Scriptures to learn God’s Way.
Everyone’s obligation is to study. The Lord told the Jews to “search the Scriptures” (John 5:39). The Holy Spirit said, “Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth” (2 Timothy 2:15). The people of Berea were commended because they “searched the Scriptures” (Acts 17:11). The Word of Christ is to dwell in us (Col. 3:16). Men err when they do not know the Bible (Matthew 22:29). Jesus rebuked people for not reading and learning (Mark 12:10). Even though Timothy had known the Scriptures since childhood (2 Timothy 3:15-17), he was still told to give attendance to reading (1 Timothy 4:13). Hebrew Christians were reproached for not knowing enough to teach others (Hebrews 5:12).
In Exodus 20:3-17, God gave a list of commandments (ten in number) to the Israelites. However, they failed in keeping them. The New Testament, on the other hand, has commandments scattered throughout its pages. Our obligation is to search them out and do them in order to be wise (Matthew 7:24-26).
We can know the truth (John 8:32). The Bible can be understood (Ephesians 3:4). It was written that men might believe (John 20:31). But it takes diligent effort to find the “pearl of great price” (Matthew 13:46). Nothing worth value comes easy. One must totally surrender their whole life to God’s Way (Matthew 6:33; Luke 9:57-62). No one will go to heaven by accident. It takes deliberate and determined effort to go there (Luke 13:23-24).
I can’t answer as to why God did not give us a list of 1, 2, 3, etc. But, the list is there just the same in the New Testament. It’s our job to “rightly divide it” and dig it out (Romans 1:18- 32).