Joshua 1:4
From the wilderness and this Lebanon even unto the great river, the river Euphrates, all the land of the Hittites, and unto the great sea toward the going down of the sun, shall be your coast. From the wilderness and this Lebanon even unto the great river, the river Euphrates, all the land of the Hittites, and unto the great sea toward the going down of the sun, shall be your coast.
Joshua received this word as he looked forward to his work with great anxiety and self-distrust. It was part of God's promise of the land of Canaan to Israel under Joshua's leadership. The inheritance he was to divide to them, as sworn to their fathers, was defined as stretching to the heights of Lebanon in the far distance, to the shores of the Great Sea westward, and eastward to the banks of the Euphrates including all the land of the Hittites, with every place the sole of their foot should tread given to them as told to Moses.
With this word God assured Joshua that He would be with him as He had been with Moses, and this removed his fears. God would make the conquest of that land easy, provided Joshua faithfully kept His commandments. The word belongs to God's own appointment of Joshua to connect with Moses in the work for His people, given by God Himself with instruction to those He calls, so that no one can take up the work of acting as Joshua on his own claim.
The territorial promise by itself does not authorize applying it to Seventh-day Adventists as a people, and such an application was rejected as a misuse of the text.