It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Those performing Hajj and Umrah are the delegates of Allah; if they supplicate, Allah Almighty answers their supplication, and if they seek forgiveness, Allah Almighty forgives them."
Salih bin Abdullah is munkar al-hadith (his narrations are rejected).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10388