It's a paralel between your wish and the exigency of others. Live according to what your heart wants and not according to what the others want you to do, others' requirements, "must do".
I agree with Freya Perhaps the parallel between what your hearts desires and what the others want you to do is already highlighted in the original text?
I can't say anything about the Greek source, my opinion was based only on the Spanish translation and I guess Tzicu-Sem translated according to the Greek text, probably.
I think the translation should also have quotation marks around the two central words of the expression. I also think "quiero" is closer to "I want" "I need" "I love" than on the word desire... And´"deber" is closer to "ought to" or "must"...
I'm lost in these comments. I think it is about several target languages.
Yes, I translated it from Greek so maybe better to check with a Greek expert...