Ibn Mas’ud reported:

The Messenger of Allah ﷺ said, “Shall I not tell you of one forbidden for Hellfire or Hellfire is forbidden for him? It is everyone accessible ( قَرِيبٍ) polite ( هَيِّنٍ), and easy-going ( سَهْلٍ).”

Source: Sunan al-Tirmidhī 2488

Abu Huraira reported:

The Prophet ﷺ said, “Whoever is kind لَيِّنًا , affable هَيِّنًا, and easy-going سَهْلًا, Allah will forbid him from entering Hellfire.”

Source: al-Sunan al-Kubrá lil-Bayhaqī 20806

All the above four qualities were present in our Prophet ﷺ and they have been summarised in one phrase in Quran:

And by the Mercy of Allâh, you dealt with them gently. And had you been severe and harsh¬hearted, they would have broken away from about you; so pass over (their faults), and ask (Allâh's) Forgiveness for them; consult them in the affairs. Then when you have taken a decision, put your trust in Allâh, certainly, Allâh loves those who put their trust (in Him)

 Surah Ali’ Imran 3 : 159

These four qualities would set us free from hellfire, though they have nothing to do with acts of worship but are related to dealings with fellow humans.

1. Polite and Affable ( هَيِّنٍ) :
   Every believing person who is polite, friendly and cordial, who meets and greets others with a cheerful face, his attitude and gait displaying self respect and humbleness, would be forbidden for Hell fire. The Qur’an says:
   And the (faithful) slaves of the Most Gracious (Allâh) are those who walk on the earth in humility and sedateness, and when the foolish address them (with bad words) they reply back with mild words of gentleness. ( Surah Furqan-63)
   
   Once there was  a small masjid in the streets of Kolkota. A person visited me.His grandfather had been correcting the aqeedah of the people of that locality. The medium of teaching was through his good Akhlaq (conduct). The story of his grandfather was like this:
   
   When this person received guidance from Allah and came to understand Touhid correctly, he started preaching it. The people started accusing him that he had a bad character and stayed away from him. He was a rich person with many servants and usually drove to his shop. When he received enlightenment, he started walking to his shop through the narrow streets. He used to clean the road while walking on his way,picking up all the litter, garbage and fruit peels that he found. He smiled at those who met him and gave money to the poor on the way. People used to watch him closely and wondered about the huge change in him. Here was the man who was well-known as a bad person but the people experienced only goodness from him. Only on the basis of his excellent character, he pulled many Non-Muslims as well as many Muslims towards the true, correct path. Within six months, he became the most sought after person in the locality.
   
   A Momin is one whose Imaan reflects even when he talks or walks.
    
2. Kind and Gentle لَيِّنًا :
   Every Believer who is kind and gentle, is soft-spoken and good tempered would be forbidden to Hellfire.. People would often desert harsh and strict superiors. Allah ordered Prophet Musa and Prophet Haroon to use soft and gentle speech even when they proceeded to meet Pharaoh, the man who was a tyrant. fakula lahu qawlun layyina - and talk to him in a soft manner
   
   Some Scholars say that in this verse, Prophet Musa, who had the highest status (at that time) has been instructed to talk kindly and gently to Pharaoh, a person of the lowest character.
   
   If we look around and examine the causes of divorces, we would find that the most common complaint is that their spouse speaks harshly with them.Backbiting, talking back and bitter criticism are some of the main causes of breaking of families.
   
   When Moulana Abul Kalam Azad was the editor of Hilal, an Urdu periodical, he wrote angrily in favor of boycotting British goods. He was among the forefront freedom fighters against the British. His article was so aggressive that people felt as if they have gone out of the fold of Islam by wearing western dresses. It was then, Moulana Sanaullah Amritsari, wrote to Abul Kalam Azad and protested politely about his aggressive stand against the Muslim youth. He added: “There is no kafir greater than Pharoah and there is no person with a status higher than Moses, yet when Allah sent Moses to Pharaoh, he instructed him to be gentle in speech.”.
   
   Polite words get a lot of honor The Prophet ﷺ said:
   The more a person has a softness in his nature and words, the more he is blessed and would be rewarded along with success. He also said - The worst person on the day of Qiyamah will be the one from whom people will abstain to be with because of his hard and bitter words.
    
3. Easy-going ( سَهْلٍ):
   A Believer who is simple and straightforward and is easy to approach to ask for help or charity, is called Sahlin and has been given the glad tidings of being forbidden to Hellfire.
    
4. Accessible ( قَرِيبٍ):
   A Believer who is good natured, simple, humble and is easily approachable would be forbidden to Hellfire. He is close to everyone and would visit sick and attend funerals and weddings irrespective of others’ financial or social status in the society. He is not egoistic. People like to be close to him and he likes to be close to people.

The point worth mentioning is that in order to be forbidden to Hellfire, these qualities have to be practised regularly, not occasionally.