Significance of associating the mention of prayer with zakat in the Qur`an
22-1-2014 | IslamWeb
Question:
Why is prayer always mentioned along with zakat in the Qur`an?
Answer:
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
In twenty-nine occurences in the Qur`an, the mention of zakat was preceded with that of prayer, except in two places wherein zakat was mentioned alone and not linked with prayer and they are (what means): {…my Mercy encompasses all things." So I Will Decree it [especially] for those who fear Me and give zakat and those who believe in Our Verses} [Qur`an 7: 156 ] and
{Those who do not give zakat, and in the Hereafter they are disbelievers.} [Qur`an 41: 7]. It would not have been mentioned alongside the prayer if it lacked importance. Therefore, such consistency, and Allaah Almighty knows best, indicates the importance of zakat in the perspective of sharia, since it is mentioned right after the prayer, which is the basic tenet of Islam for its great position in sharia.
Abu Bakr 
recognized this unique rank, which is why he fought those who refused to pay zakat during such a critical period in Islamic history. Abu Hurayrah narrated that when the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, died and Abu Bakr became the caliph, some Arabs renegaded (i.e. reverted to disbelief). ‘Umar, said to Abu Bakr 
"How can you fight these people when the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: "I have been ordered (by Allaah) to fight the people until they say: "None has the right to be worshipped but Allaah” and whoever says it will save his life and wealth from me except in what is due from him and his account will be with Allaah." Abu Bakr said, "By Allaah! If they refuse to pay me even a small sheep which they used to pay at the time of the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, I would fight them for withholding it." Then, `Umar said, "By Allaah, it was nothing more than the fact that Allaah made the decision clear in the heart of Abu Bakr (to fight) and I came to know that his decision was right." [Al-Bukhari and Muslim].
As the mention of zakat accompanied that of prayer in the Qur`an, it occurred in the Sunnah of the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, as in the narrations: "establishing the prayer and paying zakat" and "to offer the prayer and give zakat" as narrated in Al-Bukhari and Muslim and other books of Sunnah.
Allaah Knows best.