'Certain Man' in the Bible

Now there was a certain man of Ramathaimzophim, of mount Ephraim, and his name was Elkanah, the son of Jeroham, the son of Elihu, the son of Tohu, the son of Zuph, an Ephrathite:

Now a certain man of the servants of Saul was there that day, detained before the LORD; and his name was Doeg, an Edomite, the chiefest of the herdmen that belonged to Saul.

And a certain man was in Maon, and his work was in Carmel. And the man was very great, and had three thousand sheep and a thousand goats. And he was shearing his sheep in Carmel.