Albert Barnes Commentary Nehemiah 13:4

"Now before this, Eliashib the priest, who was appointed over the chambers of the house of our God, being allied unto Tobiah," — Nehemiah 13:4 (ASV)

The relations of Eliashib, the high priest (Nehemiah 3:1), with Tobiah and Sanballat will account for the absence of any reference to him either in Nehemiah 8–10, or in (Nehemiah 12:27–47).

The chamber - The entire outbuilding, or “lean-to,” which surrounded the temple on three sides (1 Kings 6:5–10).

Allied - that is, “connected by marriage.” Tobiah was married to a Jewish woman (Nehemiah 6:18), who may have been a relation of Eliashib; and his son Johanan was married to another (Nehemiah 6:18), of whom the same may be said.