He also said

When I asked Allah's Messenger ﷺ to teach me the sunna relating to the adhan he wiped the forepart of his head and said: You must say, “Allah is most great. Allah is most great. Allah is most great. Allah is most great,” raising your voice while saying these words. Then you must say, “I testify that there is no Allah but Allah. I testify that there is no Allah but Allah. I testify that Muhammad is Allah's Messenger ﷺ. I testify that Muhammad is Allah's Messenger ﷺ,” lowering your voice while saying these words. Then you must raise your voice in making the testimony, “I testify that there is no Allah but Allah. I testify that there is no Allah but Allah. I testify that Muhammad is Allah's Messenger ﷺ. I testify that Muhammad is Allah's Messenger ﷺ. Come to prayer. Come to prayer. Come to salvation. Come to salvation”; and if it is the Morning Prayer you must say, “Prayer is better than sleep. Prayer is better than sleep. Allah’s is most great. Allah is most great. There is no Allah but Allah.” Abu Dawud transmitted it.