After the Prophet (pbuh) suffered calamity at Uhud and the idolators went back, he feared that the idolators might try to come back and he said, “Who would follow them?”. Seventy men volunteered. This was recorded by Bukhari.
“Those unto whom the people said: “Verily, the people have gathered against you, therefore, fear them”. But it only increased them in faith”, (Quran 3:173).
It means, those who threatened the people, saying that the disbelievers have amassed against them, in order to instill fear in them, but this did not worry them, rather, they trusted in Allah and sought His help. Allah alone is Sufficent for us and He is the Best Disposer of affairs for us”.
Ibrahim said it when he was thrown in fire. Muhammad said it when the people said: “Verily the people have gathered against you, therefore fear them. But it only increased them in faith.
So they returned with grace and bounty from Allah. No harm touched them.
For when they relied on Allah, Allah took care of their worries, He confounded the plots of their enemies, and the muslims returned to their land. No harm touched them; safe from the wicked plots of their enemies.
“Verily Allah will help those who help his cause”. (Quran 22:40).
“O you who believe, if you help in the cause of Allah, Allah will help you”. (Quran 47:4)
“Verily we will indeed make victorious Our Messengers and those who believe, in this worlds life and on the Day when the witnesses will stand forth. The Day when their excuses will be of no profit to wrongdoers. Theirs will be the curse, and theirs will be the evil abode”. (Quran 40:51,52).
Extract taken out from tafsir ibn kathir.