Holy Ghost is a wagering theory that is used by numerologists. The suggestion is that good things happen in threes (reference to the Biblical Trinity of the Father, Son and Holy Ghost). Players of the Holy Ghost theory believe that when a certain jockey, saddle cloth number, post position, trainer, etc., scores two wins, then it follows that there will be a third success, since good luck tends to run in groups of threes.
If Vino Rosso wins for John Velazquez it will be 3 holy ghost jockeys in a row and all at good prices.
Old time track announcer Dave Johnson always used to follow this theory for jockeys.