Sunan Abi Dawud Book 2, Hadith 132
When you hear the Adhan, you should repeat the same words as the mu’adhdhin pronounces.
The supplication made between the adhan and the iqamah is not rejected.
when you hear the mu'adhdhin repeat what he says, invoke a blessing on me, for everyone who invoke one blessing on me will receive ten blessings from Allah. Then ask Allah to give me the wasilah, which is a rank in paradise fitting for only one of Allah’s servants, and I hope that I may be the one. If anyone asks Allah that I be given the wasilah, he will be assured of my intercession.