I have couple of doubts and am hoping to get an answer from you.
1. Adam and Eve ate the fruit of the forbidden tree, which is sin. Why did God has created that tree? If there is no tree, then there would have been no sin.
2. Why do the innocent suffer?
God created man to beings free to chose whether to serve God or not. God desires people who freely chose to serve Him. If God did not put the tree of the knowledge of good and evil in the garden, then there would have been no choice.
But notice that something else must also exist for man to be able to chose to follow God or to disobey Him. God had to give him a law. Without a law, no choice can exist. Right and wrong always exists, but unless we are made aware of the choice through a law, we cannot be held responsible for keeping or breaking the law. See Paul's comment on this fact in Romans 5:13. What we call sin is when a law of God is broken (see I John 3:4).
Therefore, God put the tree of the knowledge of good and evil in the garden and He gave man a law stating that eating of its fruit would produce death. God even made it easy to keep the law. It wasn't as if the tree of the knowledge of good and evil was the only source of food nearby. God put the tree in the middle of a very large garden that contained very type of flowering and fruit producing trees. Adam and Eve had to pass by may alternatives in order to chose this one tree that was off-limits.
Why do innocent people suffer? There are a variety of answers to this question:
1) They suffer because they are not truly innocent. All people sin (Romans 3:22) and sins have consequences.
2) They suffer because other people sin. The consequences of sin is broader than just the one who sins.
3) They suffer because Satan wants to bring people down (Job 1:6-12).
4) God allows suffering to strengthen His people (Hebrews 12:4-13; James 1:2-4).