I have always had this question and have grown up WELS and taught in the educational system. Why did the first man and woman God make sin?
God made Adam and Eve with the ability and freedom not to sin or to sin. Being all-knowing, God certainly knew that Satan and other angels would rebel against him, and that Adam and Eve would disobey his command. Being all-powerful, God certainly could have prevented both those falls into sin. The Bible does not provide an answer as to why God allowed sin to enter the world.
What we do know from the Bible is this: not only did God know that sin was going to enter his creation, but he formulated a plan to rescue sinners. That plan involved the sacrifice of his Son (1 Peter 1:20; Revelation 13:8). In eternity, God also graciously chose people to be members of his family (Ephesians 1:11-14).
The Bible makes it clear that people are responsible for sin (James 1:13-15). God is not guilty of any wrongdoing (Deuteronomy 32:4; Isaiah 6:3).
The Bible teaches that Eve was “deceived” by Satan (1 Timothy 2:14). Adam followed the actions of Eve (Genesis 3:6).
When it comes to the “why” questions of life and the Bible, I turn to Romans 11:33-36: “Oh, the depth of the riches of the wisdom and knowledge of God! How unsearchable his judgments, and his paths beyond tracing out! ‘Who has known the mind of the Lord? Or who has been his counselor?’ ‘Who has ever given to God, that God should repay them?’ For from him and through him and for him are all things. To him be the glory forever! Amen.” Those words tell me that while I live on this earth, I cannot expect to understand God’s ways and thoughts fully. Like you, I look forward to the time when my knowledge of God and his ways and thoughts is much different than it is now (1 Corinthians 13:12).