Ibn Majah

Commentary:
(1)
A single plucked feather of a bird is a very light thing, which even a slight breeze can turn from upright to upside down and from upside down to upright.
If it is in an open field, it is evident that the wind will have a greater effect on it, because there will be nothing to reduce the impact of the wind.
And it will be tossed about rapidly, flying here and there, from one place to another.
The human heart is in the same condition.
Various emotions and feelings rapidly influence it, due to which sometimes it inclines towards righteousness, sometimes towards sin; sometimes it is awash with the subtle emotions of love, and sometimes the storm of hatred arises.
Taking advantage of this state of the heart, Satan involves it in sins. Therefore, seeing someone steadfast on the path of righteousness, it cannot be said that he will definitely enter Paradise, nor, seeing someone immersed in sins, can it be said that he is necessarily destined for Hell. For this reason, when granted the ability to do good, one should pray to Allah for steadfastness, and if a sin occurs, one should present oneself before Allah with tears of remorse, lest the storm of sins carries him far away from mercy.

(2)
Since the states of the heart can change at any moment, a person cannot be content about his end.
It is necessary to pray for death upon faith and, at every step, to request guidance and direction from Allah, just as the Messenger of Allah (sallallahu alayhi wa sallam) used to supplicate:
(يَا مُصَرِّفَ الْقُلُوْبِ ثَبِّتْ قَلْبِيْ عَلٰي طَاعَتِكَ) (Musnad Ahmad: 2/418)
“O Turner of the hearts! Keep my heart firm upon Your obedience.”