JOEL - The "Standard of Truth" refers to the restored gospel and Church of Jesus Christ that will go forth among all the nations of the earth. There are no scriptures that specifically use that phrase, but there is a prophecy from Joseph Smith recorded in the History of the Church that states:

“The Standard of Truth has been erected; no unhallowed hand can stop the work from progressing; persecutions may rage, mobs may combine, armies may assemble, calumny may defame, but the truth of God will go forth boldly, nobly, and independent, till it has penetrated every continent, visited every clime, swept every country, and sounded in every ear, till the purposes of God shall be accomplished, and the Great Jehovah shall say the work is done” (History of the Church, 4:540).

Here are a few related scriptures:

"And even so I have sent mine everlasting covenant into the world, to be a light to the world, and to be a standard for my people, and for the Gentiles to seek to it, and to be a messenger before my face to prepare the way before me. (D&C 45: 9)

"Verily I say unto you all: Arise and shine forth, that thy light may be a standard for the nations; (D&C 115: 5)

Boyd K. Packer gave a good talk on this subject, called “The Standard of Truth Has Been Erected,” in the Nov. 2003 Ensign, p.24.