1 Samuel 20:26

Nevertheless, Saul spake not anything that day
About David's absence, took no notice of it, said nothing about it:

for he thought something had befallen him;
some impurity, some nocturnal pollution, see ( Leviticus 15:16 ) ;

he [is] not clean, surely he [is] not clean;
which he repeated in his mind for the confirmation of it, and in contempt, and to the reproach of David; and in this way he accounted for his absence the first day, and so was easy, it not being lawful and fitting for an unclean person in a ceremonial sense to eat of the peace offerings, which Saul and his family were now partaking of.