Summary of Judges 6 up to the point Gideon is puzzled why God chose him to save Israel:

During this particular time, it was the Midianites who oppressed Israel. This oppression took the form of organized bands raiding Israel and burning homes and planted fields and killing the animals. Many of the people of Israel took to hiding in caves and strongholds in the mountains. As one might guess, they were hungry due to the loss of their crops and livestock (Judges 6:1-10).

The problems had begun when the children of Israel "did evil in the sight of the Lord" (vs. 1). As things grew worse and worse, many in Israel cried out to the Lord. A prophet was sent to the people with God's message. The three part message reminded Israel that God had "delivered you" in the past and secondly they were told, "Do not fear the gods of the Amorites." Thirdly, they were told the reason for their suffering as God spoke through the prophet saying, "You have not obeyed my voice." (vss. 8-10).

Then, the Angel of the Lord appeared to Gideon at Ophrah while Gideon was threshing his wheat (vss. 11-27). Gideon is referred to as a "valiant warrior" (vss. 11-12). But this valiant warrior had a question for the Lord. Gideon's question was why had things gone so badly if God was with them (vs. 13). The Lord promised to be with Gideon and that he would defeat the Midianites (vss. 14, 16). Like many of the people God chose to work for Him, Gideon wondered "Why me?" He said his father's house was the least in the whole tribe of Manasseh and he was the youngest in the house.

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