This painting is on display in the Metropolitan Museum of Art as part of the “Painted in Mexico” exhibition that originated in Los Angeles. Jesus displays his “carnal” heart – a very popular object of veneration at this time – while a personification of the Church uses the Eucharist to send a beam of light to illuminate a bible. I like how the beam is not reflected from the pages, but is instead transformed into jagged lightning bolts that strike dead the enemies of the church (and the Jesuits, who supported the cult of the sacred heart against its opposition.)
The image of Jesus is a direct adaptation of this earlier, less complex picture.
The sacred heart, representations of which originated in the middle ages, was at first shown iconographically, i.e. as a stylized heart shape, but eventually become anatomically correct. Not quite clear on whether this is a bleeding heart…
Up on the roof, there is a different, more ironic sort of veneration going on.