Charles Spurgeon Commentary 1 Samuel 20:5-6

"And David said unto Jonathan, Behold, to-morrow is the new moon, and I should not fail to sit with the king at meat: but let me go, that I may hide myself in the field unto the third day at even. If thy father miss me at all, then say, David earnestly asked leave of me that he might run to Beth-lehem his city; for it is the yearly sacrifice there for all the family." — 1 Samuel 20:5-6 (ASV)

And David said unto Jonathan, Behold, tomorrow is the new moon, and I should not fail to sit with the king at meat: but let me go, that I may hide myself in the field unto the third day at even. If thy father at all miss me, then say, David earnestly asked leave of me that he might run to Bethlehem his city: for there is a yearly sacrifice there for all the family.

The family of David was a godly household, and they had a meeting, not for pleasure-making, but for sacrifice; a special family gathering for worship, and David had to be there. He spoke no untruth; he did desire to go to Bethlehem.