Psalm 69:10, "When I wept and I fasted, that was to my reproach," speaks to the Psalmist's experience of being mocked and scorned even when he was demonstrating sincere repentance and piety.

Here's a breakdown of what the verse means:

"When I wept and I fasted...": This refers to the Psalmist's acts of humility, repentance, and seeking God. Weeping and fasting were common practices to show sorrow for sin and a desire to draw closer to God.
"...that was to my reproach.": "Reproach" means shame, disgrace, scorn, or insult. Instead of being seen as righteous or drawing sympathy, the Psalmist's acts of piety were used against him. People mocked him for his devotion and suffering, twisted his actions, and used them as a reason to further humiliate him.

In essence, the verse highlights the painful irony of being persecuted for your faith or genuine efforts to connect with God. It conveys the idea that the Psalmist's enemies actively twisted his sincere religious practices to shame and ridicule him.

Possible Interpretations and Context:

Hypocrisy/Misinterpretation: The Psalmist's enemies might have accused him of hypocrisy, suggesting that his weeping and fasting were insincere or done for show.
Lack of Understanding: They might simply not have understood his religious devotion and considered it weak, foolish, or even dangerous.
Political Opposition: His piety could have been viewed as a threat to the status quo or to the political power of his enemies.
A righteous man is mocked: The Psalm is a lament and a plea for deliverance. The Psalmist is suffering unjustly, and his attempts to seek God through repentance are even used to ridicule him.

Overall, the verse illustrates the unfair treatment the Psalmist received and the pain of being mocked for his faith and efforts to do what is right. It's a common theme throughout the Psalms that resonates with anyone who has faced opposition or ridicule for their beliefs or values.