Preference is a type of Advantage. Advantage is related to Lucky. Lucky is a synonym of Successful. 
Prayer is related to Grace. Grace is etymologically related to Grateful. Grateful is similar to Glad. 
Preference --IsA--> Advantage <--RelatedTo--> Lucky <--Synonym--> Successful 
Prayer <--RelatedTo--> Grace --EtymologicallyRelatedTo--> Grateful <--SimilarTo--> Glad 