Great Regulars: But there is also a baraita

that holds the opposite: "When a person puts on his shoes, he puts on his right shoe and after this he puts on his left shoe." Given the conflict, the law is that either procedure is acceptable. But, Rav Nachman bar Yitzchak insists, "One who fears Heaven can fulfill both directives." How? By following the example of Mar son of Rabana: "He would put on his right shoe, but not tie it; and then he would put on his left shoe and tie it; and then he would tie his right shoe." Thus Mar could say that, in a way, each shoe was put on before the other.

from Adam Kirsch: Tablet: Does God Care About Shoes?

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