1) Six Etiquettes of Learning 
Imaam Ibn al-Qayyim - rahimahullâh - said,
“There are six stages to knowledge:
Firstly: Asking questions in a good manner.
Secondly: Remaining quiet and listening attentively.
Thirdly: Understanding well.
Sixthly - and it is its fruit: Acting upon the knowledge and keeping to its limits.”
2) Fruits of Humility
Ibn al-Qayyim - rahimahullâh - said, "One of the Salaf (Pious Predecessors) said,
‘Indeed a servant commits a sin by which he enters Paradise; and another does a good deed by which he enters the Fire.’
It was asked, ‘How is that?’ So he replied,
‘The one who committed the sin, constantly thinks about it; which causes him to fear it, regret it, weep over it and feel ashamed in front of his Lord - the Most High - due to it. He stands before Allâh, broken-hearted and with his head lowered in humility. So this sin is more beneficial to him than doing many acts of obedience, since it caused him to have humility and humbleness – which leads to the servant’s happiness and success – to the extent that this sin becomes the cause for him entering Paradise. As for the doer of good, then he does not consider this good a favour from his Lord Upon him. Rather, he becomes arrogant and amazed with himself, saying, 'I have achieved such and such, and such and such'. So this further increases him in self adulation, pride and arrogance – such that this becomes the cause for his destruction.’”
3) Purifying the Heart
Ibn al-Qayyim (rahimahullâh) said,
“There is no doubt that the heart becomes covered with rust, just as metal dishes – silver, and their like – become rusty. So the rust of the heart is polished with dhikr (remembrance of Allâh), for dhikr polishes the heart until it becomes like a shiny mirror. However, when dhikr is abandoned, the rust returns; and when it commences then the heart again begins to be cleansed. Thus the heart becoming rusty is due to two matters: sins and ghaflah (neglecting remembrance of Allâh). Likewise, it is cleansed and polished by two things: istighfâr (seeking Allâh’s forgiveness) and dhikr.”
4) Jihâad Against the Self
“Jihâd (striving) against the soul has four stages:
Firstly: To strive in learning guidance and the religion of truth, without which there will be no success. Indeed, there can be no true happiness, nor any delight in this world and in the Hereafter, except through it.
Secondly: Striving to act upon what has been learnt, since knowledge without action will not benefit, rather it will cause harm.
Thirdly: Striving to invite others towards it and to teach those who do not know, otherwise he may be considered from those who hide what Allâh has revealed of guidance and clear explanation. Such knowledge will neither benefit, nor save a person from the punishment of Allâh.
Fourthly: Striving to be patient and persevering against those who oppose this da‘wah (call) to Allâh and those who seek to cause harm - patiently bearing all these hardships for the sake of Allâh.
When these four stages are completed then such a person is considered to be amongst the Rabbâniyyûn. The Salaf were agreed that a Scholar does not deserve the title of Rabbânî until he recognises and knows the truth, acts upon it, and teaches it to others. So whosoever has knowledge, acts upon it, and teaches this knowledge to others, is considered from the Rabbâniyyûn.”
5) Trials of the Heart
Ibn al-Qayyim said, whilst commenting upon the following hadîth, “Trials and tribulations will be presented to hearts, as a reed mat is interwoven stick by stick. Any heart which absorbs these trials will have a black mark put in it. However, any heart that rejects them will have a white mark put in it. The result is that hearts will be of two kinds: one white like a white stone, which will not be harmed by trials as long as the heavens and earth endure; and the other dark and rusty, like an over-turned vessel; not able to recognise the good, nor reject evil, but rather being absorbed with its desires.” 
“The fitan (trials) which are presented to the hearts - and which are the cause of its weakness - are,
(i) the trials relating to shahwah (false desire) and
(ii) the trials relating to shubhah (doubt)... so the first causes intentions and will to be corrupted, whilst the second causes knowledge and beliefs to be corrupted”.
Speaking about such trials, he (rahimahullâh) said,
"Hearts - when exposed to such fitân (trials) – are of two types,
[The first type]: A heart, which, when exposed to such trials, absorbs it like a sponge that soaks-up water, leaving in it a black stain. Such a heart continues to soak-up the various trials that are presented to it, until it becomes dark and corrupted - which is what is meant by “an over-turned vessel.” So when this occurs, two dangerous and deadly diseases take hold of it and plunge it into destruction:
Firstly: confusing good with evil, so it neither recognises the good, nor rejects the evil. This disease may take hold of it to such an extent that it believes good to be evil; and evil to be good, Sunnah (Prophetic Guidance) to be bid‘ah (innovation), and innovations to be the Sunnah; and the truth to be falsehood: and falsehood the truth.
Secondly: judging by its whims and desires, over and against what Allâh’s Messenger came with being enslaved by its whims and desires and being led by them also.
[The second type]: A white heart in which the light of eemaan (faith) is bright and its radiance is illuminating. So when trials are presented to such a heart, it rejects and turns away from them. This further increases its light and illumination and its strength.”
6) Four Principles of Worship
“The verse “You alone do we worship.” [Sûrah al fâtihah 1:5] is built upon four principles,
Ascertaining what Allâh and His Messenger love and are pleased with, from,
i. the sayings of the heart
ii. the tongue
iii. actions of the heart
iv. actions of the limbs.
So al-‘Ubûdiyyah (servitude and slavery to Allâh) is a comprehensive term for all these four stages. The one who actualises them has indeed actualised, “You alone do we worship.”
The saying of the heart: It is I‘tiqâd (belief) in what Allâh, the Most Perfect, informed about His Self; concerning His Names, His Attributes, His Actions, His Angels, and all that He sent upon the tongue of His Messenger.
The saying of the tongue: It is to inform and convey (what Allâh has revealed), to call to it, defend it, to explain the false innovations which oppose it, to establish its remembrance and to convey what it orders.
The action of the heart: Such as love for Him, reliance upon Him, repenting to Him, having fear and hope in Him, making the Deen (religion) purely and sincerely for Him, having patience in what He orders and prohibits, having patience with what He decrees and being pleased with it, having allegiance and enmity for His sake, humbling oneself in front of Him and having humility in front of Him, becoming tranquil with Him and other than this from the actions of the heart which are actually connected to the action of the limbs ... and actions of the limbs without the action of the heart is of little benefit if any benefit at all.
The action of the limbs: Such as Prayer and Jihâd, attending the Jumu‘ah and being with the Jamâ‘ah (the main body of the Muslims), aiding those who are unable and displaying goodness and kindness to the creation, and other than this.”
 Miftâh Dârus-Sa‘âdah ( p.283).
 Al-Wâbilus-Sayyib minal-Kalimit-Tayyib ( p. 15).
 Al-Wâbilus-Sayyib (p. 80).
 Zâd ul-Ma‘âd fî Hadî Khayril-‘Ibâd (pp. 9-11).
 Related by Muslim (no. 144), from Hudhaifah, radiallâhu ‘anhu.
 Ighâthatul-Luhfân (p. 40).