Stanza 1 is a prayer for renewal by the Holy Spirit (see PHH 420); stanza 2 continue this prayer with allusions to Romans 8:9-17.
Bert Polman, Psalter Hymnal Handbook
Since it is uniquely the work and passion of the Holy Spirit, who is “our Sanctifier by living in our hearts” (Belgic Confession, Article 9) and “by the work of the Holy Spirit [God] regenerates us and makes us new creatures, causing us to live new life and freeing us from the slavery of sin” (Belgic Confession, Article 24), we plead for his power to continue this work. The Holy Spirit restores us into God’s image “so that with our whole lives we may show that we are thankful to God for his benefits, so that he may be praised through us...” (Heidelberg Catechism, Lord’s Day 32, Question and Answer 86). We come to know, therefore, that our growth in holy living will not occur without the Holy Spirit’s ministry.