Calling the Athaan with one's shoes on is permissible
19-7-2014 | IslamWeb
Question:
As-salaamu alaikum, One day I gave Azaan in Jamiat Ahl-ul-Hadeeth in Delhi. After Azaan one old man very angrily rebuked me for wearing sandals which pronouncing Azaan. He told me the same sandal you wear and go to toilet and here you are giving Azaan, you should have removed it! However, I gave Azaan outside of Masjid as it was customary and probably my sandals were dry. Jazaak ALLAHU Khair.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
You bear no sin for calling the Athaan with your shoes on and you were not obliged to take them off before calling the Athaan. The shoes are fundamentally pure (unless proven otherwise). Some scholars highlighted that the shoes which are worn in the bathroom are predominantly impure and are rarely pure. However, the Islamic Sharee'ah overlooks the ruling of predominance in this case and considers the ruling of rareness. Al-Qaraafi 
wrote, “The shoes worn in bathrooms are impure in general even though we cannot always perceive the impurity itself. Being free of impurity is a rare case. However, the Islamic Sharee'ah discards the ruling of what is more likely and affirms the ruling of what is less likely (in this case) as a manifestation of the mercy of Allaah and in order to promote easiness. So, one may perform prayer in such shoes without the need to wash them.” [Al-Furooq]
Even if you assume that the shoes were impure, the purity of the body and clothes is not a condition for the validity of the Athaan but is rather recommended. According to Kashshaaf Al-Qinaa‘ (a book on the Hanbali Fiqh), “It is recommended for the Mua’ththin (one who calls the Athaan) to purify his body and clothes before raising the Athaan.”
However, we advise you to keenly avoid in the future anything that will detract from your reputation among poeple (by making them think evil of you) even if it is lawful, and avoiding what is forbidden is required with a greater reason. We also advise you to shun what might be a reason for triggering Fitnah (discord) or sowing the seeds of dissension and enmity so as to ward off evil and foster the brotherly bond between you and your fellow Muslims, especially the elderly, given their right to be respected.
Moreover, if it is permissible for the Muslim to avoid some of the recommended matters in order to win people’s hearts, then shunning what is forbidden is required with even greater reason. Shaykhul-Islam Ibn Taymiyyah said, “A Muslim may not do what is recommended if doing it would incur graver evil that outweighs the sought benefit, just like what the Prophet, sallallaahu ‘alayhi wa sallam, did with regard to rebuilding the Ka‘bah according to the foundations laid by Prophet Ibraaheem (Abraham) 
. The Prophet, sallallaahu ‘alayhi wa sallam, said to ‘Aa’ishah 
: “Had your people not been still close to the pre-Islamic age of ignorance, then I would have demolished the Ka‘bah, bringing it to the level of the ground and rebuilt it with two doors, an entrance and an exit.” [Al-Bukhari and Muslim] Thus, the Prophet, sallallaahu ‘alayhi wa sallam, gave up the opinion that he believed to be the best of the two options and adopted the other one given its outweighing benefit. That is, the people of Quraysh were close to the pre-Islamic era and the idea of demolishing the Ka'bah would have driven them to become averse to Islam. Hence, the evil consequences were more probable than good ones. Therefore, Imaam Ahmad and other scholars 
ruled that it is favorable for the Imaam to give up what he sees as a better choice, if this would foster more accord and rapport for those led in prayer.” [End quote]
Allaah Knows best.