This hadith shows the mercy of Allah Almighty whereby He Subhanhu Wa Ta’ala gives such great reward and makes paradise compulsory for a person in return for such a small action which requires little effort. This does not mean that the utterance of these words is sufficient, one must also act upon these words by worshipping Allah Almighty alone and making Him unique in Lordship, Worship and in His names and attributes (this is being pleased with Allah as our Lord), following the Shariah of Islam and striving to perform that which it orders and avoid that which it prohibits (this is being plesed with Islam as our religion) and following the Sunnah of the Messenger (sal Allahu alaihi wa sallam) and taking his path and rejecting all other paths (this is being pleased with Muhammad (sal Allahu alaihi wa sallam) as our Prophet).
A person who is focused on this life always feels poor because of seeing all that he does not have of it; he is not focused on Jannah, nor believing in it or striving for it. Since he believes it is he himself who has to do what he can to gather the riches of this world his outlook and behaviour are selfish. Selfishness begets selfishness. Those who are preoccupied with getting the most for themselves induce the same feelings in those around them. Thus, nobody sincere wants to be around a person preoccupied with his worldly life and its achievements. Such a person gets in life what Allah (subhana wa ta’ala) had destined for them a long time ago, but not Allah’s special blessings to be bestowed in the next life.