Zakat is coupled with Prayer and Piety
رُوِيَ عَنِ الإِمَامِ الصَّادِقِ أَنَّهُ قَالَ :لاَ صَلاَةَ لِمَنْ لاَ زَكَاةَ لَهُ، وَلاَ زَكَاةَ لِمَنْ لاَ وَرَعَ لَهُ
It has been narrated from Imam Sadiq (A.S), that he said: “There is no prayer for whom there is no zakat; and there is no zakat for whom there is no piety.”
Bihar al-Anwar, Volume 81, Page 252
Other links:
The Special Rank of Prayers