This verse from 1 Chronicles 26:20 describes a specific role held by a Levite named Ahijah within the administrative structure of the temple. Let's break down what it means:

"Of the Levites..." This indicates that Ahijah belonged to the tribe of Levi. The Levites were designated to serve in the temple and assist the priests in various duties.
"...Ahijah was over the treasures..." This signifies that Ahijah held a position of authority and responsibility related to the storage and management of valuable items.
"...of God's house..." This refers to the Temple itself. Ahijah was in charge of the treasures specifically designated for the general upkeep, functions, and embellishment of the Temple.
"...and over the treasures of the dedicated things." This is a separate category of treasures. "Dedicated things" were items (money, objects, land) that had been vowed or set apart for a specific religious purpose. This could include offerings, donations, or items used in rituals.

In essence, the verse tells us that Ahijah was a Levite official whose job was to manage and safeguard the valuable possessions of the Temple, as well as those items specifically dedicated for religious purposes.

Significance:

Organization: This verse highlights the highly organized nature of the Temple administration. There were specific individuals responsible for different aspects of its operation, including the management of its wealth.
Trust and Responsibility: Ahijah's role required a great deal of trust and accountability. He was entrusted with protecting and managing valuable assets that belonged to God and the community.
Support of Worship: The treasures under Ahijah's care were essential for maintaining the Temple and ensuring that the religious rituals could be carried out properly.

In short, Ahijah was a key administrator in the Temple who oversaw the financial resources and dedicated items, playing a crucial role in supporting the Temple's operations and religious practices.