From the last 1999 issue of a known Skeptical publication we have an item on Mark 2:25-28:

And he said unto them, Have ye never read what David did, when he had need, and was an hungred, he, and they that were with him? How he went into the house of God in the days of Abiathar the high priest, and did eat the showbread, which is not lawful to eat but for the priests, and gave also to them which were with him? And he said unto them, The sabbath was made for man, and not man for the sabbath: Therefore the Son of man is Lord also of the sabbath.

Skeptic X offers one of the familiar complaints here, but also two new ones; let's go over these:

• refers to this story in terms of "situational ethics" in that he supposes Jesus is justifying lawbreaking behavior on the Sabbath. only treats this briefly here, so we will as well: What is at issue in this story is the weighing of a situation to say whether it is indeed a matter of immorality. The rabbis of the day also weighed absolute needs even as we do: Is it allowed to rescue an animal from a hole on the Sabbath? No, because it was a matter of life and death for the animal. This is a matter of priority discussed by the rabbis and Jesus is far from engaging "situational ethics" as defines it (apparently, in terms of justifying an immoral act) but rather has to do with a hierarchy of morals, which is not the same thing.
• On Abiathar see here.
• Finally, error is claimed in the phrase, "and gave also to them which were with him." 1 Samuel 20:1-5 suggests that there were men with David, but argues that this was a lie by David, and that the contexts of 1 Samuel 20-21 "make it clear David was alone on his flight and fabricated companions" to get help from the priest. How? Here is his reasoning, such as it is:
  1. David asks for only five loaves of bread, and thinks it "rather unlikely...How long would that have lasted a contingent of any size?" It would have lasted a contingent of five to ten men a full day, enough to get them to their next destination for food (David, a popular hero, would have had many allies), which is all that really matters. Unless wants to somehow hypothesize a huge group and no other stopping points possible, he's just beating the air.
  2. It is supposed that if men were sent from Jonathan, they already would have had food and weapons with them and there would be no need to ask for any. One wonders whether X thinks that ancient people left food and weapons just lying around. Food was precious and carefully measured and guarded. Weapons were at a premium as well. There is no basis for thinking any contingent would have food and weapons with them already, or else only carried enough to get them to David quickly -- Saul surely wasn't opening the coffers for any large group with recognizable or possible allies of David.
  3. The passage goes on to say that David fled for Gath, and it mentions no one else. Apparently X still hasn't learned the language of representation in Hebrew thought -- I suppose we should also suppose that Pilate personally scourged Jesus (John 19:1).
  4. X supposes that Dave would not have been afraid of the king of Gath, Achish, with a contingent of men with him, and would have "commanded some respect" from the city. Sure, if the contingent numbered in the thousands, but no one argues that. Five or ten would command no respect and would be the right size for an escape party that didn't want to be noticed, and will still have reason to be fearful if things went wrong. can't seem to moderate his imagination.
  5. It is noted that the king of Gath, Achish, mentions no one other than David. Well, why should he? X needs to explain unequivocally why these men should have been mentioned. Did they do anything worth beans while there? Is the author obliged to remind us for the sake of people who can't think their way through?

See more here including a link to a response from X.