Why has Salat and Zakat been mentioned together repeatedly in the Qur’an?

From the five pillars, the Qur’an mentions the three pillars of Iman, Salat and Zakat together repeatedly. The great scholar, Imam al-‘Iraqi (d.806 AH) states that whoever performs these three pillars correctly, will be able to perform fasting and Hajj easily. Al-Kirmani (d.786 AH) mentions Salat and Zakat have more importance and emphasis due to their universal nature. It is of no surprise then that the Qur’an exhorts steadfastness on Salat and Zakat twenty-eight times. In fact, Mulla Ali al-Qari (d.1014 AH) states that Salat and Zakat are the origins of all worship and good deeds . Imam al-‘Ayni (d. 855 AH) refers to Zakat as the partner of Salat . If Salat and Zakat are rightfully established at a macro and micro level in the society, they will help in all other good deeds and acts manifesting in society. It is upon this establishment of virtue which Allah promises prosperity and harmony for all. “God has made a promise to those among you who believe and do good deeds: He will make them successors to the land, as He did those who came before them; He will empower the religion He has chosen for them; He will grant them security to replace their fear. ‘They will worship Me and not join anything with Me.’ Those who are defiant after that will be the rebels. Establish Salat, give Zakat and obey the Messenger so that you may receive [this] Mercy!” (Quran 24:55-56).