• qaṭṭ: an adverb of past time meaning “ever/never before”; the ṭāʾ is doubled and the word is indeclinable with ḍamma.
• ’anfasu minhu: that is, better or more valuable than it; nafīs refers to something noble, excellent and eagerly prized.
• lā junāḥ: no blame and no sin.
• ghayru mutamawwil, ghayru mutaʾaththil: a mutamawwil is someone who acquires money in excess of his need, while taʾaththul is to hoard capital and keep it until it becomes as though old and established in one’s possession.

Overall meaning
ʿUmar ibn al-Khaṭṭāb, may Allah be pleased with him, acquired a tract of land in Khaybar amounting to one hundred shares. Because of its fertility and quality it became the dearest of all his wealth to him; the Companions—may Allah be pleased with them—used to vie in performing the enduring righteous deeds.
So he went to the Prophet ﷺ, desiring the righteousness mentioned in the Almighty’s words, “You will never attain piety until you spend of that which you love” (Q 3:92), and sought his counsel on how best to devote the land purely for Allah’s sake, trusting fully in the Prophet’s perfect advice.
The Prophet ﷺ directed him to the noblest form of charity: to lock the principal and turn it into a waqf, so that it could not be sold, gifted, inherited, or otherwise transferred, while its yield would be given to the poor and the destitute, to relatives and kinsfolk, to the emancipation of captives—whether by manumitting slaves or by paying the required blood-money—, to those striving in Allah’s path to raise His word and support His religion, to travellers whose funds have run out away from home, and to guests as well, for honouring one’s guest is part of faith in Allah.
Because such property needs someone to manage, irrigate and maintain it, the hadith removes blame from its custodian if he eats from it reasonably and feeds a friend, on condition that he does not thereby seek to amass wealth beyond his need. The waqf exists solely for spending in avenues of goodness and beneficence, not for accumulation and enrichment.

Lessons derived from the hadith
1 From the words, “If you wish, hold its principal in trust and give its yield in charity,” we learn the very definition of waqf: the principal is withheld while the benefit is released.
2 From the words, “Its principal is not to be sold, given away, or inherited,” we learn the ruling concerning disposal of the endowed property: transferring its ownership or engaging in any act that leads to such transfer is impermissible. It remains binding and operative in accordance with the endower’s stipulation, provided that stipulation entails no injustice or partiality.
3 The proper subject-matter of waqf is a tangible asset that endures after its benefit has been taken. Whatever is consumed through use is ordinary charity and does not share the nature or ruling of waqf.