How come God can tell me what to do?
Here's the answer:
God can tell us what to do because He is God. He created us and knows what is best for us.
The commands in the Bible teach us how to think, how to treat people, and how to honor God.
God’s commands in the Bible show us what is right and how to please Him. God, as our Creator, has given us the instructions on how to live a righteous life. For example, the Bible tells us to love our neighbors as we love ourselves (Matthew 22:39). When we treat others with respect and love, God is honored.
Another command is for children to obey their parents (Ephesians 6:1). We can understand that our parents are smarter than we are and we should follow their counsel. When we disobey our parents, we are dishonoring God. Unless our parents are asking us to sin, we are to obey them.
"'Teacher,' he [an authority on the law] asked, 'which is the most important commandment in the Law?' Jesus replied, '"Love the Lord your God with all your heart and with all your soul. Love him with all your mind." This is the first and most important commandment. And the second is like it. "Love your neighbor as you love yourself." Everything that is written in the Law and the Prophets is based on these two commandments'" (Matthew 22:36-40).