The hymn is sung to the tune "An Wasserflüssen Babylon." Here's the fourth musical phrase:
In the first verse, the text here is "None else the burden sharing." "Burden" is sung with a descending melisma (C Bb A), musically representing a sort of bending beneath this weight.
In the fourth verse, the text is "My joy beyond all measure!" Here, "all" is sung with a melisma (Bb A), lending a slight sense of entirety. Additionally, the phrase "all measure" is sung to notes of all different pitches (Bb A G F), also giving a sense of breadth.
The line "O Love, how strong You are to save!" near the end of the third verse bears some resemblance to part of Psalm 31:2: "Be a rock of refuge for me, a strong fortress to save me!"
