Background:
Darius I, also known as Darius the Great, was the king of Persia from 522 to 486 BC. His reign is noted for the consolidation and expansion of the Persian Empire, as well as significant administrative reforms. In the biblical context, Darius is recognized for his role in the continuation of the rebuilding of the Jewish temple in Jerusalem, a project initially authorized by Cyrus the Great.

Biblical Context:
The instructions of Darius to Tattenai, the governor of the region beyond the River (Euphrates), are recorded in the Book of Ezra. This event occurs during the post-exilic period when the Jewish exiles had returned from Babylon to rebuild the temple in Jerusalem. The rebuilding had faced opposition and was halted until the second year of Darius' reign.

Scriptural Account:
In Ezra 5, Tattenai, along with Shethar-bozenai and their associates, questioned the Jews about who had authorized the reconstruction of the temple. The Jewish leaders referred to the decree of Cyrus. Tattenai then wrote to Darius, seeking confirmation of this decree.

Ezra 6:1-12 records Darius' response after a search of the royal archives confirmed Cyrus' decree. Darius issued a new decree, instructing Tattenai and his associates not to interfere with the work on the temple. He commanded:

1. Non-Interference: "Do not interfere with the work on this house of God. Let the governor of the Jews and the Jewish elders rebuild this house of God on its original site" (Ezra 6:7).

2. Provision of Resources: Darius ordered that the expenses for the rebuilding be fully paid from the royal treasury, from the revenues of the region beyond the River, ensuring that the work would not stop (Ezra 6:8).

3. Support for Sacrifices: He also instructed that whatever was needed for the burnt offerings of the God of heaven—young bulls, rams, lambs, as well as wheat, salt, wine, and oil—be provided daily without fail (Ezra 6:9).

4. Prayer for the King and His Sons: Darius requested that the Jews offer prayers for the life of the king and his sons (Ezra 6:10).

5. Penalty for Disobedience: A severe penalty was decreed for anyone who altered the edict: "A beam is to be pulled from his house, and he is to be impaled on it. And for this crime, his house is to be made a pile of rubble" (Ezra 6:11).

Significance:
Darius' instructions to Tattenai highlight the providential hand of God in the affairs of nations, ensuring the fulfillment of His purposes. The decree not only facilitated the completion of the temple but also underscored the authority of the Persian king in supporting the Jewish community's religious practices. This event is a testament to God's faithfulness in restoring His people and re-establishing worship in Jerusalem, as prophesied by the prophets.

Theological Implications:
From a theological perspective, Darius' decree serves as an example of how God can use secular authorities to accomplish His divine will. It reflects the biblical theme of God's sovereignty over earthly kingdoms and His ability to turn the hearts of kings to favor His people (Proverbs 21:1). The support for the temple's reconstruction also emphasizes the importance of worship and the centrality of the temple in the life of Israel.