It is narrated from Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Two supplications are not rejected - or he said: are not turned back - the supplication at the time of the call to prayer, and the supplication at the time of battle, when parts of it close in on one another." Musa bin Ya'qub said: Ruzayq bin Sa'id bin Abd al-Rahman also narrated this hadith to me, from Abu Hazim, from Sayyiduna Sahl bin Sa'd (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), who said: "And under the rain." Imam al-Tabarani (may Allah have mercy on him) said: Ruzayq has no musnad marfu' hadith except this one hadith, and another hadith that is munqati' (broken in its chain).
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5735