Jai Jinendra.

When someone is doing Atthai/Attham (intense Jain fast), you can respectfully greet and encourage them with short, traditional blessings like:

• Jai Jinendra, Tapasvi Pranam.
• Uttam Tap!
• Dharma Labh.
• Aapka tap safal ho, veerya badhe.
• Samyak tap ki siddhi ho.
• Shata labh!
• Gujarati: “Uttam tap! Tapasvi pranam; veerya vadhse.”
• Sanskrit/Prakrit style: “Vīrya-vardhanam astu.”

Etiquette:

• Speak softly and briefly; avoid discussing food or offering it.
• Offer practical help (quiet space, needed items).
• If during Paryushan/Das Lakshan, you may also say “Michhami Dukkadam” to seek/extend forgiveness.

Note: Both Shwetambar and Digambar traditions use similar respectful phrases like “Uttam Tap,” “Dharma Labh,” and “Tapasvi Pranam”; exact wording varies by local language, but the intent—honor the tapasvi’s vow and encourage right effort—remains the same.