It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "When the servant stands for prayer, the gates of Paradise are opened for him, the veils between him and his Lord are lifted, and the wide-eyed maidens (al-hur al-'in) come to welcome him, as long as he does not blow his nose or spit."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7949