What is required in the third commandment?

Answer

The third commandment requires the holy and reverent use of God's names (), titles, attributes (), ordinances (), Word (), and works (; ).

Read the 6 proof texts (KJV)

Psalm 29:2: Give unto the LORD the glory due unto his name; worship the LORD in the beauty of holiness.
Revelation 15:3-4: ³And they sing the song of Moses the servant of God, and the song of the Lamb, saying, Great and marvellous [are] thy works, Lord God Almighty; just and true [are] thy ways, thou King of saints. ⁴Who shall not fear thee, O Lord, and glorify thy name? for [thou] only [art] holy: for all nations shall come and worship before thee; for thy judgments are made manifest.
Ecclesiastes 5:1: Keep thy foot when thou goest to the house of God, and be more ready to hear, than to give the sacrifice of fools: for they consider not that they do evil.
Psalm 138:2: I will worship toward thy holy temple, and praise thy name for thy lovingkindness and for thy truth: for thou hast magnified thy word above all thy name.
Job 36:24: Remember that thou magnify his work, which men behold.
Deuteronomy 28:58-59: ⁵⁸If thou wilt not observe to do all the words of this law that are written in this book, that thou mayest fear this glorious and fearful name, THE LORD THY GOD; ⁵⁹Then the LORD will make thy plagues wonderful, and the plagues of thy seed, [even] great plagues, and of long continuance, and sore sicknesses, and of long continuance.