Charles Ellicott Commentary Numbers 9:10

"Speak unto the children of Israel, saying, If any man of you or of your generations shall be unclean by reason of a dead body, or be on a journey afar off, yet he shall keep the passover unto Jehovah." — Numbers 9:10 (ASV)

In a journey afar off. —Or, on a distant journey. This is one of the ten passages in the Pentateuch in which one or more words are marked with certain dots, known as puncta extraordinaria. In this case, these dots stand over the word rehokah, distant. The Rabbinical explanation is that the word is either spurious, as not being found in Numbers 9:13, or is not to be interpreted in its literal meaning, but in a qualified sense.