O you who believe! If you help God(’s cause by striving in His cause), He will help you and make your feet firm (so that you are steadfast in His cause and ultimately victorious)
Know that, if the believers help God [how generous of the One Who does not need help to consider a person’s move toward Him as help], God will help them in return and will strengthen their foothold
Faridul Haque
O People who Believe! If you help the religion of Allah, He will help you and will stabilise you
Hasan Al-Fatih Qaribullah
Believers, if you help Allah, He will help you and strengthen your feet
O believers! If you help Allah, He will help you; He will keep your feet firm.
Al-muntakhab fi tafsir al-Qur'an al-Karim
O you who believe with hearts impressed with religious and spiritual virtues: if you intend to direct your minds and thoughts to striving in the cause of Allah and to make His purpose the heart of your purpose, He will help you defend your final cause and help you take a firm position and set your feet firm