Open ye the gates. The command is given by God to his angels within the city, or perhaps by some angels to others, to "open the gates," and let the saints march in and take possession (comp. Psalms 118:19, Psalms 118:20, which seems to represent the same occasion; and Psalms 24:7-10, which tells of another occasion on which the angelic warders were bidden to throw open the gates of the celestial city.
The righteous nation which keepeth the truth; literally, a righteous nation. A people, made up of all kindreds and nations and tongues, which should henceforth be "the people of God" They are "righteous," as washed clean from all taint of sin in the blood of the Lamb.
They "keep the truth," or "keep faithfulness," as under all circumstances clinging loyally to God.