Without context, I'd say it may be a reference to the Son of God in the Bible. 聖 itself is tacked to the front of many people or things that suggests "absolute/ultimate/most high etc".
You have Confucius (as Bruce mentioned), or any other person that has attained the pinnacle of literary and moral excellence (聖人). Or used as a description for imperial power (like 聖上,二聖臨朝). Or Christmas even (聖誕).
Now you know what 聖 means, you can go ahead and add 子 and come up with your conclusion~