The third verse contains various metaphors of what the Lord's words are, and near the end of the verse, there's the line "Yes, they are my sword prevailing." This description refers to part of Ephesians 6:17: "the sword of the Spirit, which is the word of God."
The hymn's fourth verse ends with the lines "May I daily sing Your praise, / From my heart glad anthems raise, / Till my highest praise is given / In the endless joy of heaven." The line "Till my highest praise is given" is sung to this musical phrase:
The first syllable of "highest" is sung to the highest note in the phrase (Bb), so there's a sense of its meaning, although here it seems to be more metaphorical than literal.
