His seed shall be mighty upon earth. The phrase used of Nimrod in Genesis 10:8, but not necessarily to be taken in exactly the same sense; rather as gibor hail in Ruth 2:1 and 1 Samuel 9:1, "wealthy, prosperous."
The generation of the upright shall be blessed; i.e. shall receive blessing from the Most High, and shall therefore prosper. To be blessed in one's seed was, under the old covenant, the highest of blessings.