The painting depicts the three angels who visited Abraham, but it is full of Christian symbolism. The figure at the center of the painting could be interpreted as Jesus with his two fingers extended to represent his human and divine natures.
Throne of Mercy, Albrecht Dürer, 1511
The "Throne of Mercy" was a common way of depicting the Trinity from the 16th century until the 18th century. The Father is shown holding the cross or a dying Christ while the Holy Spirit is represented by a dove flying above them.
The Trinity, El Greco, 1577-79
The Holy Family (The Seville Virgin), Bartolomé Esteban Murillo, 1665 - 1670
The Holy Family is depicted along with God the Father and the Holy Spirit as a dove.
Trinity, Hendrick van Balen, 1620
The Holy Spirit is often depicted as a dove, and God the Father as an older white-haired man.
Holy Trinity, Lorenzo Lotto, c.1519-1520
This painting was created as an altarpiece for the church of San Spirito in Beragmo, Italy.
Holy Trinity, fresco by Luca Rossetti da Orta, 1738-9
The Gonzaga Family Worshiping the Holy Trinity, Peter Paul Rubens, 1604-1605