Thus in the end...
Thus in the end, the 'love of self' would actually be a source for encroachment upon the rights and possessions of others, pride and jealousy. Truly, 'love of self' is the source of all corruption and is the mother of all calamities. Question: If 'love of self' does not manifest in a person and an individual ends up not 'loving his self' then he will definitely not strive to attain anything in this life.
For example, obeying Allah (SwT) is for the salvation of the self; attaining knowledge is for a person to become a scholar. Thus in summary, all struggles and endeavors stem from the 'love of self'. If this trait of 'love of self' cannot exist, then no one would put forth efforts in life! Therefore, in summary we can state that the 'love of self' is actually the driving force for a person. Hence, how can you claim that 'love of self' is the source of all sins!?
Answer: The 'love of self', when taken to an extreme is the mother of all calamities. Sometimes a person develops such a love of his self that he forgets about other people, and this is what is the source of corruption, pride, miserliness, etc… and becomes the greatest of spiritual veils for a person while on the path towards Allah (SwT).
In summary, if a person pays excess attention to himself then he will definitely not be able to (spiritually) see Allah (SwT) since the trait of individualism is the opposite of keeping Allah (SwT) in mind and heart. Thus, the outcome of this extreme and excessive form of 'love of self' manifests itself in the trait of not showing equity to others and this is the greatest impediment in the advancement of a person.
Therefore, if we wish to be the complete manifestation of these words of the Prophet (S), then we must, even when it comes to discussions of knowledge, show equity and fairness.
For example, if something comes into my mind and the theory or belief is something which I strongly believe in - even if the proofs for that thought or belief are weak however another person says something different and proofs which he brings forth to prove his point are very strong, if I was not to show equity in regards to this discussion of knowledge, then I would definitely not pay any attention to what this other person is saying to me!
Thus in this example, I have shown that there is no justice present in my discussions and studies… Within scholarly discussions, the only time that a person is able to reach to the truth contained of an issue is when he shows equity.