I haven’t spoken privately or in some dark corner of the world.  Isaiah 45:19.  Another translation – I have not spoken in secret, In a corner of a land of darkness.  That is God speaking.

The Apostle Paul, under arrest in Caesarea, appeared before King Agrippa II in his own defense against charges brought by the Jewish priests. As he was recounting what he had done to oppose Jesus of Nazareth and of his own encounter with the Lord on the road to Damascus, Paul indicates that he was certain the king knew what he was talking about regarding Jesus and His followers:

FOR THE KING, BEFORE WHOM I ALSO SPEAK FREELY, KNOWS THESE THINGS; FOR I AM CONVINCED THAT NONE OF THESE THINGS ESCAPES HIS ATTENTION, SINCE THIS THING WAS NOT DONE IN A CORNER. ACTS 26:26

In Luke 23 the Judas led crowd that came to arrest Jesus was confronted by him with these words -“When I was daily with you in the temple, ye stretched forth no hands against me: but this is your hour, and the power of darkness.”

The Gospel is a public thing, publically proclaimed and not something to be ashamed of even though it is a scandal and foolishness to those who do not know God.  They however live to hide in a corner and whisper.  They are psithuristés and if you get a chance to hear them they have the lisping whispering voice of a snake charmer. psithuristés Is onomatopoeia. Onomatopoeia, is the process of creating a word that phonetically imitates, resembles, or suggests the sound that it describes. Such a word itself is also called an onomatopoeia. Common onomatopoeias include animal noises such as oink, meow, roar, and chirp. People apart from God hide in a corner and, imitating the voice of the serpent in the garden, they speak behind the back to destroy reputations.  They are gossips.