Being religious or not, one has to appreciate religion for giving the impetus to the existence of all this art. In Prado, there is no way of getting around religion. And each painter seems to have his Pieta in there, pick and choose the one you like! My two favorite ones are Flemish, Van der Weyden´s Descent from the Cross - that was originally destined for Isabella the Catholica and Fernando's burial chapel in Granada:
And Anton van Dyck´s Pieta, that beats them all - maybe not Michel Angelo's, but that's in a different register:
And the last, but not least in this religious feast - Caravaggio. Only one painting of his exposed in Prado, like Rembrandt´s, but an impressive one. Used less to inspire religious faith, but to rather show his aesthetic standards, it stays in my memory, David and Goliath:
Hmm, so again no time to even start speaking about Velasquez, El Greco, and Rubens...it will have to wait for a Prado 3 intervention!