But when the Pharisees heard that He had silenced the Sadducees, they gathered together. Then one of them, a lawyer, asked Him a question, testing Him, and saying, “Teacher, which is the great commandment in the law?” Jesus said to him, “‘You shall love the Lord your God with all your heart, with all your soul, and with all your mind.' This is the first and great commandment. And the second is like it: ‘You shall love your neighbor as yourself.’ On these two commandments hang all the Law and the Prophets.”
The truth is that we haven't always loved God with all of our hearts and all of our souls and all of our minds, and we haven't always loved our neighbors as we should. Sin (by definition) is transgression against the law - God's law.
Romans 3:23 For all have sinned and fallen short of the glory of God.
Today, start by understanding that you are a sinner. See that you have sinned. Humble yourself and go to God repenting of your sins. Look to Jesus who loves you and died for you. Look to Him in faith as your only means of Salvation.