“And it came to pass, that when David was come to the top of the mount, where he worshipped God, behold, Hushai the Archite came to meet him with his coat rent, and earth upon his head:”
King James Version (KJV)
15:30 Barefoot - In testimony of his deep sorrow, and humiliation and shame for his sins.
15:34 And say - That is, as faithful to thee, as I have been to thy father. David's suggesting this crafty counsel must be reckoned amongst his sins. Nevertheless God was pleased to direct this evil advice to a good end.