وَلَا يَجُوزُ أَدَاءُ الزَّكَاةِ إِلَّا بِنِيَّةٍ مُقَارِنَةٍ لِلْأَدَاءِ، أَوْ مُقَارِنَةٍ لِعَزْلِ مِقْدَارِ الْوَاجِبِ.
Translation: Payment of zakat is not valid without intention accompanying the payment, or accompanying the separation of the amount due.
Because zakat is an act of worship, it is distinct from an ordinary financial transfer. An intention of zakat is required at the time of payment, or at the moment the due amount is set aside for zakat.
Muqaranah means the intention accompanies the relevant act. The passage recognizes two relevant moments: payment and earmarking the obligatory amount.