Deuteronomy 28:45 Moreover all these curses shall come upon thee, and shall pursue thee, and overtake thee, till thou be destroyed; because thou hearkenedst not unto the voice of the LORD thy God, to keep his commandments and his statutes which he commanded thee:
God wanted to bless His people. He had first told them that if they would obey He would do all sorts of great things to and for them. After the positive came the negative warning. If they chose not to listen to the voice of the Lord, to not keep His commandments, then they would be cursed, destroyed.
They would be cursed everywhere they went and in everything that they did. Their disobedience would affect their children. If they persisted in wickedness, not only would God withhold His blessings, but He would see their sin destroy them. There would be pests to ruin their crops. There would be sickness. The rains would cease. They would get sick. They would lose their way. Their families would be destroyed. Their economy would be severely affected.
Basically, if they wanted to rebel, then they would become the laughingstock of their neighbors. Their joy would be gone. They would become servants and borrowers. They would pay a horrible price for their decision to disobey God.
Sin always has horrible consequences. If you feel like you get away with sin, just remember that the effects of sin may be slow in coming, but they will come. Honor God with your life by obeying Him.