The hymn is sung to the tune "Auf, auf, mein Herz." Here's the fourth musical phrase:
In the third verse, the text here is "The joy within my heart" (continuing the sense from the previous line: "Now nothing ever saddens"). "Joy" is sung with a melisma (B C#), lending a sense of this ebullience.
In the sixth verse, the text is "Whate'er He passes through" (again continuing the sense from the previous line: "My Lord will leave me never"). "Whate'er" is sung with a melisma, and each note is a different pitch (A B C#). Both aspects of this articulation provide a sense of breadth.
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I wrote about the Biblical sources for the hymn text before, but I also noticed that the line "He who is strong to save" in the second verse bears some resemblance to part of Psalm 31:2: "Be a rock of refuge for me, a strong fortress to save me!"