Saul's servant - Josephus calls him one of Saul's freedmen. The difference this would make in Ziba's position would only be that instead of paying in the fruits of the confiscated land to David, he would have to pay them to Mephiboseth.

I have given unto thy master's son - Unless Ziba had been servant of Jonathan, this seems to refer to Micha, son of Mephibosheth, and so some understand it; but it is more likely that Mephibosheth is meant, who is called son of Saul instead of grandson. Yet it is evident enough that the produce of the land went to the support of Micha, (see 2 Samuel 9:10), for the father was provided for at the table of David; but all the patrimony belonged to Mephibosheth.

Then the king called to Ziba, Saul's servant,.... Who had been his servant:

and said unto him, I have given unto thy master's son; meaning either, as some, the son of Mephibosheth, Micha after mentioned; or rather Mephibosheth himself, the grandson of Saul, whose servant Ziba had been:

all that pertained to Saul, and to all his house; all his paternal estate, or what he had acquired, or in any wise belonged to him and his family; which David had in possession, and which he readily and cheerfully delivered up to Mephibosheth, having so great a regard to the memory of his father.

David then summoned Ziba the servant of Saul, told him of the restoration of Saul's possessions to his son Mephibosheth, and ordered him, with his sons and servants, to cultivate the land for the son of his lord. The words, "that thy master's son may have food to eat," are not at variance with the next clause, "Mephibosheth shall eat bread alway at my table," as bread is a general expression, including all the necessaries of life. Although Mephibosheth himself ate daily as a guest at the king's table, he had to make provision as a royal prince for the maintenance of his own family and servants, as he had children according to 2 Samuel 9:12 and 1 Chronicles 8:34. Ziba had fifteen sons and twenty servants (2 Samuel 9:10), with whom he had probably been living in Gibeah, Saul's native place, and may perhaps have hitherto farmed Saul's land.

Then the king called to Ziba, Saul's servant, and said unto him, I have given unto thy master's son all that pertained to Saul and to all his house.

9:9-13 As David was a type of Christ, his Lord and Son, his Root and Offspring, let his kindness to Mephibosheth remind us of the kindness and love of God our Saviour to fallen man, to whom he was under no obligation, as David was to Jonathan. The Son of God seeks this lost and ruined race, who sought not after him. He comes to seek and to save them!