If I were baptized by St. Peter and someone else were baptized by Judas, as no doubt happened, then, although Judas is a scoundrel and St. 
Peter is a righteous apostle of Christ, yet Judas does not therefore make the Baptism bad. Likewise, the fact that St. Peter is a saint applies only to himself personally and in no way helps or applies to Baptism. On the other hand, the fact that Judas is Christ’s betrayer does hurt the baptism which others received from him. The Donatists, however, said that Judas is ungodly therefore his Baptism is not real either. Yet St. Augustine says, “Christ retained Baptism for Himself, that we might know that the minister’s ungodliness is not detrimental to the Sacrament.”
Martin Luther, sermon delivered on Epiphany 3, January 27, 1538
Benjamin T.G. Mayers Martin Luther on Holy Baptism: Sermons to the People (1525-39) 68-69