Tafsir of verse 40
Al-Mukhtasar
If you O believers, do not help the Messenger (peace be upon him) and respond to his call to strive for the sake of Allah, then Allah has already helped him when you were not with him; when the idolaters drove him away from Mecca with Abū Bakr aṣ-Ṣiddīq (may Allah be pleased with him), and the two of them hid in the cave of Thawr from the disbelievers who were chasing them. On that occasion, the Messenger of Allah (peace and blessings be upon him) told his companion Abū Bakr, who was scared that the idolaters would discover him, not to worry, because Allah was with them, supporting and helping them. Allah sent down His reassurance and tranquility upon the heart of His Messenger, and sent angels which they could not see to support them, making the word of the idolaters the lowest, and the word of Allah the highest by aiding His Religion. Allah is Mighty in His essence, power and force – nothing can overcome Him – and He Wise in His planning, decree and laws.
Tafsir of the whole Surah At-Tawbah
Other translations of verse 40
If you do not support the Prophet, Allah has already supported him when the disbelievers forced him out; when he was second of the two38 in the cave – saying to his companion, “Do not grieve; Allah is with us.” Thereupon Allah sent down His tranquility upon him, supported him with soldiers that you did not see39, and rendered the word of the disbelievers40 the lowest, whereas the Word of Allah41 is supreme. And Allah is All-Mighty, All-Wise.
Notes
[38] The second was his companion, Abu Bakr.
[39] Angels came to the Prophet’s aid in the small cave.
[40] i.e., their claims and slogans of disbelief.
[41] i.e., "La ilaha illa Allah" (There is no true deity except Allah).
If you help him (Muhammad صلى الله عليه وسلم) not (it does not matter), for Allâh did indeed help him when the disbelievers drove him out, the second of the two; when they (Muhammad صلى الله عليه وسلم and Abu Bakr رضي الله عنه) were in the cave, he (صلى الله عليه وسلم) said to his companion (Abu Bakr رضي الله عنه): "Be not sad (or afraid), surely Allâh is with us." Then Allâh sent down His Sakînah (calmness, tranquillity, peace) upon him, and strengthened him with forces (angels) which you saw not, and made the word of those who disbelieved the lowermost, while the Word of Allâh that became the uppermost; and Allâh is All-Mighty, All-Wise.
If ye help him not, still Allah helped him when those who disbelieve drove him forth, the second of two; when they two were in the cave, when he said unto his comrade: Grieve not. Lo! Allah is with us. Then Allah caused His peace of reassurance to descend upon him and supported him with hosts ye cannot see, and made the word of those who disbelieved the nethermost, while Allah's Word it was that became the uppermost. Allah is Mighty, Wise.
If ye help not (your leader), (it is no matter): for Allah did indeed help him, when the Unbelievers drove him out: he had no more than one companion; they two were in the cave, and he said to his companion, "Have no fear, for Allah is with us": then Allah sent down His peace upon him, and strengthened him with forces which ye saw not, and humbled to the depths the word of the Unbelievers. But the word of Allah is exalted to the heights: for Allah is Exalted in might, Wise.
If you will not aid him, Allah certainly aided him when those who disbelieved expelled him, he being the second of the two, when they were both in the cave, when he said to his companion: Grieve not, surely Allah is with us. So Allah sent down His tranquillity upon him and strengthened him with hosts which you did not see, and made lowest the word of those who disbelieved; and the word of Allah, that is the highest; and Allah is Mighty, Wise.
In case ever you do not vindicate him, (The prophet) yet Allah readily vindicated him, as the ones who disbelieved drove him out the second of two, as the two were in the cavern, as he said to his companion, "Grieve not; surely Allah is with us. "Then Allah sent down His serenity on him and aided him with hosts you did not see; and He made the word of the ones who disbelieved the basest; and the Word of Allah is that (which) is The Uppermost; and Allah is Ever-Mighty, Ever-Wise..