3- Obeying Allah The Almighty and avoiding His prohibitions: acts of worship are like food for the heart, while sins are like poison that kills it. Allah The Almighty Says (what means):
• {O you who have believed, respond to Allah and to the Messenger when he calls you to that which gives you life. And know that Allah intervenes between a man and his heart and that to Him you will be gathered.} [Quran 8:24]
• {But if they had done what they were instructed, it would have been better for them and a firmer position [for them in faith].} [Quran 4:66]
Thus, obedience to Him makes a person firm and strong when facing tribulations, whereas negligence and disobedience of Allah The Almighty weakens a person in confronting temptations.
4- Frequent remembrance of Allah The Almighty, as He Says (what means):
• {O you who have believed, remember Allah with much remembrance * And exalt Him morning and afternoon. * It is He Who confers blessing upon you, and His angels [ask Him to do so] that He may bring you out from darknesses into the light. And ever is He, to the believers, Merciful.} [Quran 33:41-43]
• {Unquestionably, by the remembrance of Allah hearts are assured.”} [Quran 13:28]
Allah The Almighty even ordered Mosa (Moses) and Harun (Aaron), may Allah exalt their mention, to evoke Him regularly when He sent them to Pharaoh, Saying (what means): {Go, you and your brother, with My signs and do not slacken in My remembrance.}[Quran 20:42]
Therefore, He also commanded believers to do the same when contending with disbelievers, Saying (what means): {O you who have believed, when you encounter a company [from the enemy forces], stand firm and remember Allah much that you may be successful.} [Quran 8:45]
The frequent remembrance of Allah The Almighty, then, strengthens the heart and body in the face of temptations, trials and enemies.
5- Keeping company with virtuous scholars who practice what they preach: learned men are the heirs of Prophets and they guide their followers to the way of Allah The Almighty.
Anas, may Allah be pleased with him, relates: “No sooner had we finished burying the Prophet, sallallahu ‘alayhi wa sallam, that we felt something unusual in our hearts [i.e., trepidation and lack of assurance].” Why would that not be so, when, as Allah The Almighty Says (what means): {Certainly did Allah confer [great] favor upon the believers when He sent among them a Messenger from themselves, reciting to them His verses and purifying them and teaching them the Book and wisdom, although they had been before in manifest error.} [Quran 3:164]
Shaykh Sa‘eed Hawwa may Allah have mercy upon himexplains the sentiments of Anas, may Allah be pleased with him: “This indicates that the improvement of the heart depends on keeping company with those who adhere to what is right and being spiritually associated with them. Therefore, we stress the importance of being attached to upright scholars and the devout.”
Similarly, Imam Ibn Al-Qayyim wrote, describing his teacher Shaykhul-Islam Ibn Taymiyyah may Allah have mercy upon them both: “Whenever we panicked and started having ill thoughts about Allah The Almighty, we would go to him. Once we saw him and listened to him, we would no longer feel that way; instead those emotions would transform into strength, happiness, conviction and confidence.”
There are many other factors that help a person remain steadfast on the truth, but we will suffice with these here.