Is there any basis in the Qur’an and Sunnah for the saying that whoever claims a blessing has been taken from him will actually have it taken from him, such as feigning illness or claiming poverty? And what is the way to preserve blessings?

There is no basis for the saying: "Whoever lies and claims that a blessing has been taken from him, it will then truly be taken from him." And the hadith (definition) that conveys this meaning, "Do not feign illness, lest you become ill; and do not dig your graves, lest you die," is denounced and unauthentic. It is incumbent upon a Muslim not to show anything contrary to the blessing bestowed upon them, for fear that it might be an act of ingratitude leading to its removal. For ingratitude for blessings is a cause for their disappearance, as Allah Almighty said: "And Allah presents an example: a city that was safe and secure, its provision coming to it in abundance from every location, but it denied the favors of Allah. So Allah made it taste the garb of hunger and fear for what they used to do." As for preserving blessings, its cause is to give thanks for them by acknowledging them in the heart, praising the Bestower with the tongue, and using them in obedience. Allah Almighty said: "If you are grateful, I will surely increase you [in favor]."