In A.D. 630 the Holy Prophet decided to lead an expedition to Tabuk on the Syrain border. In order to finance the expedition the Holy Prophet invited contributions and donations from his followers.
Umar had then considerable wealth with him, and he thought that was the occasion for him to excel Abu Bakr in the matter of donation in the way of God.
Umar went home and he returned loaded with considerable wealth. When the Holy Prophet asked him how much he had left for himself and his family, he said that he had given one half of his wealth in the way of Allah, and had left one half for himself and his dependents. The Holy Prophet was much pleased at the contribution, and he thanked Umar profusely.
Then Abu Bakr came carrying his contribution, and the Holy Prophet put to him the same question as to how much wealth he had left for himself and his family. Abu Bakr said, "I have brought all that I had. I have left Allah and His Prophet for myself and my family."
This episode has formed the theme of one of the poems of Allama Iqbal. The last verse of the poem reads:
"For the moth the lamp, and for the nightingale the flower,
For Siddiq, God and His Prophet alone suffice."
The call to arms was given at a very inconvenient time. The weather was burning hot. Crops were ripe and ready for harvesting. The journey to the Syrian border was long and arduous. Many persons preferred to stay back. In spite of obstacles and difficulties, an army of thirty thousand persons was raised.
The Muslim army reached Tabuk after a weary march.
There was no Byzantine force to meet the Muslims. On coming to know of the advance of the Muslim army, the Byzantines had withdrawn their army well within Syria. The Muslims achieved their object without firing a shot.
The Byzantincs who had at one time threatened to invade Arabia were no longer in the mood to measure swords with the Muslims. The tribes in the region which were under the paramountcy of the Byzantines transferred their allegiance to the Muslims.
At Tabuk, the Holy Prophet delivered a classical address which has passed into history. He said:
"Verily the most veracious discourse is the Book of Allah.
The most trusty stronghold is the word of piety.
The best of religions Is the religion of Islam.
The best of the precedents is the precedent of Muhammad.
The noblest speech is the invocation of Allah.
The finest of the narratives is the Quran.
The best of the affairs is that which has been firmly resolved upon.
The worst in religion are those things which are created without sanction.
The best of the ways is the one trodden by the Prophets. The noblest death is the death of a martyr.
The most miserable blindness is the waywardness after guidance.
The best of the actions is that which is beneficient.
The best guidance is that which is put into practice.
The worst blindness is the blindness of the heart."