On the seventh day: this can mean either on the seventh day of the life of the child or on the seventh day of his illness. Since the latter is much more likely, it is probably best to translate “seven days later” or “after seven days of sickness.”

Servants of David: that is, the officials of King David’s court mentioned in the previous verse.

Behold: see the comments on verse 11 above.

The question how then can we say to him the child is dead? is not intended to give the idea that these officials were looking for the proper words to use to inform the king of the death of his son. Rather they were saying, in effect, “We cannot tell him that the child is dead!”

Do himself some harm: literally “do evil” (so Fox), but the reference is obviously to doing evil to himself. This final sentence in verse 18 may be rendered in some languages as “He may do something bad to himself if we tell him that the child is dead” or “If we tell him that his son has died, he may injure himself.”

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on the First and Second Books of Samuel, Volume 2. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here .