Understanding and application

What is the main purpose of جَزَاكَ اللَّهُ خَيْرًا in Hadith 208?

Salawat, Mosque Service, Good Character, and the Trust of Knowledge (Hadith 206–213)

• Rejecting help
• Criticizing the helper
• Cancelling a debt without consent
• Praying that the benefactor receives good reward