In this artwork, how is the Style discussed?
The work was the first narrative based work to appear at Orsanmichele.  In its execution Verrocchio showed sophisticated knowledge of the style and substance of classical sculpture.  The figures were cast without backs (i.e., not in the round) as they were only to be viewed from the front.  This had the added benefits of saving on bronze (which was roughly ten times more expensive than marble), making the work lighter and easier to fit into the niche.
The interaction between the characters of Christ and St Thomas show a strong sense of movement and dialogue.  Differences between the mortal and the immortal are highlighted with Christ's passive, almost regal stance and the agitated and nervous disposition of the doubting St Thomas. The realism created by the artist is indicative of the period of art in which it was made, the Renaissance.
Renaissance Orsanmichele classical sculpture