Final answer:
The line 'Nor with aught else can our souls interknit' is a metaphor for spiritual bonding, indicating a deep and profound connection between souls on a spiritual level.
Step-by-step explanation:
The line 'Nor with aught else can our souls interknit' is a metaphor for spiritual bonding. In this context, 'aught else' refers to anything else outside of the souls, indicating that the connection between souls is unique and cannot be achieved through any other means. The phrase suggests a deep and profound connection between individuals on a spiritual level.