Ibn Majah

Commentary:
(1)
According to some researchers, this narration is of the rank of hasan, which is considered authoritative by the hadith scholars. However, the last part of this hadith (وَإِنَّ الرَّجُل...) — "A person is deprived of sustenance due to his bad deeds" — is not established by any reliable chain of transmission. Rather, Shaykh al-Albani rahimahullah has written regarding it that it is fabricated (mawdu‘).
For details, see: (al-Sahihah, Hadith: 154; al-Da‘ifah, Hadith: 179)

(2)
Just as the reward of good deeds results in elevation of ranks and eternal blessings in the Hereafter, similarly, due to good deeds, Allah Ta‘ala bestows blessings, honor, and further ability to do good in this world as well. Likewise, the punishment for bad deeds is received in both this world and the Hereafter, except if Allah Ta‘ala forgives.

(3)
Various meanings of increase in lifespan have been mentioned.

(a)
That is, there is blessing (barakah) in the lifespan, and it is spent in good deeds and saved from being wasted.

(b)
One is granted the ability to do good deeds, due to which reward continues to reach him even after death, as Allah Ta‘ala has said:
﴿وَالبـقِيـتُ الصّـلِحـتُ خَيرٌ‌ عِندَ رَ‌بِّكَ ثَوابًا وَخَيرٌ‌ أَمَلًا﴾ (al-Kahf: 46)
"The enduring good deeds are better with your Lord in reward and better in hope."

(c)
The lifespan that was known to the angels or the Angel of Death is increased.
This is an increase from the perspective of the angels; Allah Ta‘ala already knew that this person would perform such-and-such good deed, and as a reward for it, his lifespan would be increased by such-and-such amount.

(4)
The meaning of changing destiny (taqdir) is that the calamity which a person fears is averted due to the blessing of supplication (du‘a), and a calamity that has already come is removed.
Just as Prophet Yunus alayhis salam was saved from the belly of the fish due to supplication.
Allah Ta‘ala said:
﴿فَلَولَا أَنَّهُ كانَ مِنَ المُسَبِّحينَ - لَلَبِثَ فى بَطنِهِ إِلى يَومِ يُبعَثونَ﴾ (al-Saffat: 143, 144)
"If he had not been among those who glorify (Allah), he would have remained in its (the fish's) belly until the Day they are resurrected."
Here too, it can be said that this change is according to the knowledge of the angels, not a change in the knowledge of Allah.
Allah Ta‘ala already knew that such-and-such person would supplicate, and then his difficulty would be resolved.

(5)
This contains encouragement for supplication (du‘a), and it is also understood that supplication is among the permissible means, the adoption of which is not contrary to reliance (tawakkul), rather it is the very essence of tawakkul.

Commentary:
Benefit:
For the detailed research discussion and benefits and rulings of the aforementioned hadith, refer to the benefits and rulings under Hadith: 90.