There are canonized saints, who are usually patrons of something. For example-St. Matthew is the patron of accountants. So if one was looking for intercession or special help with matters of accounting, or shares something in common with St. Matthew, you could seekhis interscession
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Sometimes a saint chooses us-they may be known to be a patron of somethignwe have no connection to, but we are led to them, and perhaps read about their lives and find a connection that is not well known.
There are many other saints that we don’t know about that are not officially patrons. Being a saint means you are in heaven. We all try to become saints.