When you read the previous reading from Ezekiel and my commentary, you better understand how Jesus Christ appears in judgment, as seen by John in the vision of the Book of Revelation.
And he had in his right hand seven stars: and out of his mouth went a sharp two-edged sword: and his countenance was as the sun shineth in his strength.
God, throughout scriptures, prepares the way for greater and greater understanding of his will, which culminated, of course, in the bodily presence of Jesus Christ, and the giving of the Holy Spirit to the disciples at Pentecost.
So here is a perfect example where you can see how God explains the analogy of his judgment being like a sword to Ezekiel, and then John witnessing the glorified judging Jesus Christ in heaven, in preparation for the end of time, with a sharp sword in his mouth.
An explanation of the specification that Jesus has a "two-edged sword" is needed because again moderns do not understand what was well understood in Biblical times.
A two-edged sword is a sword that can cut on both sides. Many swords have only one cutting edge, and so if one is in a fight, one must always turn that side toward the opponent in order to cut them.
A two-edged sword implies swiftness of striking the opponent, because when both sides are sharp, one does not need to turn the sword or return to position to strike the opponent again. With a two-edged sword one can stroke, for example from left to right across an opponent's body cutting with the "right" edge of the sword, and then in the same motion draw back across the opponent's body from right to left, cutting with the left edge, which is the leading edge. In other words, a two-edged sword means you can lead and inflict the strike with either edge.
Thus John is noticing that Jesus Christ has out of his mouth a two-edged sword, which means great swiftness and totality of judgment.