Albert Barnes Commentary Psalms 118:19

"Open to me the gates of righteousness: I will enter into them, I will give thanks unto Jehovah." — Psalms 118:19 (ASV)

Open to me the gates of righteousness ... — The gates of the house devoted to a righteous God; the gates of a house where the principles of righteousness are strengthened, and where the just emotions of the heart may be expressed in the language of praise. Compare the notes at Isaiah 26:2. The language here may be regarded as addressed to those who had charge of the house of the Lord — the priests — requesting that they would open the doors and permit him to enter to praise God for his mercy. Compare Isaiah 38:20.