St. Spyridon of Tremithus and Elder Gabriel.
I recall another case of his help when I was working on the icon, “The Glory of the Most Holy Trinity”. That icon depicts St. Spyridon of Tremithus and Elder Gabriel. As is generally known, one of the most significant events of the First Oecumenical Council of 325 was the speech of St. Spyridon, who exposed the heresy of Arius, which argued that Christ was created by God the Father and was not equal to Him. Many philosophers were on the side of Arius and by false logical inferences tried to reject the arguments in favor of the Triune God. It seemed the argument was nearing deadlock… But St. Spyridon of Tremithus demonstrated the unity of the Holy Trinity for everybody to see. He took a brick into his hands, squeezed it—and in an instant fire shot out of it, water dripped on the ground, and clay remained in the saint’s hands. “There are three elements of which one brick is composed. Likewise, in the Holy Trinity there are Three Persons but only One God,” the wonderworker proclaimed.
There was a similar episode in the life of Elder Gabriel. It was testified to by Archimandrite Kirion (Oniani). Once some Hindus who were visiting the elder asked him, “Fr. Gabriel, what will you answer if we say that you Christians are mistaken? Though you Orthodox adopted the idea of the Trinity from us, you misunderstood the teaching of Brahma, Vishnu and Shiva; the Hindu triad, despite the harmonic connection, has no unity, whereas you consider the Trinity as triune, which is a basic mistake.”
Fr. Gabriel replied: “You are wrong! Our teaching is Divine, otherworldly and came from the Lord. How can there be any mistake here? But, since you don’t believe this and are so self-confident, I will also answer with a demonstrative example.” Fr. Gabriel took bread from a pan, put it on a tray and said: “You see: the bread is one and undivided!” Then in the Name of the Most Holy Trinity he made the sign of the cross over the bread—and water, fire and wheat appeared in its place! Then Fr. Gabriel addressed the Hindus, who were dumbstruck at the sight, “Look attentively! Water, fire and wheat have appeared instead of bread. Likewise, the Holy Trinity is divided into Three Persons: the Father, the Son, and the Holy Spirit.” Next in the Name of the Holy Trinity he made the sign of the cross over the water, fire and wheat—and they turned into bread again. After that the elder said: “The Most Holy Trinity is One and Undivided just as this bread is one and undivided!”
Source: https://orthochristian.com/131345.html