That he who blesseth himself in the earth - That is, he who shall invoke blessings on himself.
Shall bless himself in the God of truth - Or by the true God. He shall not seek a blessing from a false god; but he shall come before the true God, and seek a blessing at his hand.
And he that sweareth - Every oath that is taken in the land shall be by the true God. There shall be no swearing by idols; but the true God shall be everywhere acknowledged.
Because the former troubles are forgotten - The former punishments and calamities shall be passed away. The favor of God shall be restored. His pure worship shall be re-established, and his name shall be celebrated again in the land. The image here is one of returning prosperity and favor; a state when the happiness will be so great that all the former trials will be regarded as not worthy of recollection.