From the morals and manners of the salaf was that they would constantly search their souls to breed in them the characteristics of the believers, and to discard the characteristics of the hypocrites. One is the opposite of the other. A summary of the believers characteristics is mentioned in His Great Book saying:
"Those who turn (to Allah) in repentance; that serve Him, and praise Him; that wander in devotion to the cause of Allah; that bow down and prostrate themselves (in prayer); that enjoin good and forbid evil; and observe the limits set by Allah - so proclaim the glad tidings to the believers." [Al-Qur'an 9:112]
"The believers will be successful. Those who humble themselves in their prayers; who avoid vain talk; who are active in deeds of charity, who abstain from sexual relations except with those joined to them in marriage or (the captives) whom their right hands possess, for (in their case) they are free from blame. But those whose desires exceed those limits are transgressors. Those who faithfully observe their trusts and their covenants; who (strictly) guard their prayers: these will be the heirs who will inherit Paradise, to dwell therein." [Al-Qur'an 23:1-11]
In the hadith, "None of you truly believes until he loves for his brother what he loves for himself." [Al-Bukhari and others.]
Al-Hafidh Ibn Hajar said in Fath ul-Bari, "The fact that negating complete iman and negating the name of a thing meaning negating completeness and perfection is derived from the Arabic language as is said, Such and such is inhuman."
The Prophet sallallahu 'alayhi wa sallam said, "By Allah! He does not believe. By Allah! He does not believe. By Allah! He does not believe." He was asked, "Who, O Messenger of Allah?" He, sallallahu 'alayhi wa sallam, said, "Whoever does not safeguard his neighbour from his harms." [Al-Bukhari and Muslim. Muslim's version reads, "He will not enter Paradise if he does not spare his neighbour from his harms."]
Yahya ibn Mu'adh rahimahullah gathered the characteristics of the believers in one of his essays as follows, "It is to be full of modesty, and to be harmless too. To be full of goodness and not to be corrupt. For the tongue to be truthful, for the words to be little and to be plentiful in good action. To have little slip-ups and not to be excessive. To be good to one's relatives, building closeness between them. To be dignified and grateful. To be full of contentment if Allah restricted some provision. To be forbearing and friendly to his brothers. To be compassionate and chaste. Not to curse, swear, insult, backbite, nor to gossip. Not to be hasty, envious, hateful, arrogant nor vain. Not to lean towards worldliness, nor to extend long hopes and wishes. Not to sleep too much nor to be absent-minded, nor to show-off nor be hypocritical. Not to be selfish, but to be soft and cheerful, not servile. Loving for the sake of Allah, being pleased for His sake and being angry only for His sake. His provision is taqwa (reverential fear of Allah). His worries are what will happen to him in the Afterlife. His friends remind him. His beloved is His Protector and Master. His struggle is for the Afterlife."
Fudayl ibn 'Iyad rahimahullah said, "A believer plants a palm tree and fears that thorns will grow. The hypocrites plant thorns expecting ripe dates to grow!"
O brother! Realise these facts and search yourself carefully before your death. Weep over your soul if you find in it the morals of the hypocrites. Increase in seeking His forgiveness.
All praise be to Allah Lord of the Worlds.