Sequence
The previous verse Ali 'Imran 3:7 ⧉ mentioned 'those well-grounded in knowledge' who, in spite of their excellent knowledge, were not proud of their excellence. Instead of that, they elected to have faith in what comes from their Lord. The present verse Ali 'Imran 3:8 ⧉ mentions yet another excellence of theirs - that they pray for steadfastness on the right path, not for any worldly gains, but for salvation in the life-to-come.
Commentary
The first verse Ali 'Imran 3:8 ⧉ shows us that guidance and straying are from Allah alone. When Allah intends to guide someone, He makes his heart tilt towards what is good and right; and when He decides to let someone go astray, He turns his heart away from the straight path.
This is just as it was said in a hadith of the Holy Prophet ﷺ There is no heart which is not there in between the two of Allah's fingers - He makes it firm on the truth as long as He wills, and turns it away from the truth when He wills.
He is Allah, absolute in power. He does what He wills. Therefore, those who are concerned about how to remain firm in their faith, they go to the source - requesting and praying Allah for steadfastness. The Holy Prophet ﷺ always used to pray for it as it appears in a hadith: یامقلب القلوب ثبت قلوبنا علی دینک ( O reverser of hearts, make our hearts firm on the faith chosen by You). (Mazhari)