1-The Prophet ﷺ, said:

“Islam is built upon five pillars: Witnessing that there is no god but Allah and that Muhammad is His servant and Messenger, and establishing the prayer…”
‎[ Agreed upon.]

2- salat is the best of actions.

The Prophet ﷺsaid:

“The best of actions is the prayer early in its time.”
‎ [ Source: At-Tirmidhi.]3- As-Salah is the line between Islam and Kufr (disbelief).

The Prophet ﷺ said:

“Indeed between a man, and shirk and Kufr, is abandoning the prayer.”
[ Source: Muslim.]4- The foundation of Islam is built on As-Salah and At-Tawheed (worshipping only Allah, alone).

The Prophet ﷺ said:

“The head of this affair is Islam and its support is Salah .”‎
[ Source: Ahmad.]