Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(He it is Who quickeneth) for the resurrection (and giveth death) in the life of the world. (When He ordaineth a thing) when He wants to create a child without a father, such is the case with Jesus, (He saith unto it only: Be! and it is) a son without a father! And it is also said that this means: when He wants the Day of Judgement to happen, He simply says: Be! And it is.
He it is Who gives life and brings death. So when He decides upon a matter, [when] He wants to bring something into existence, He only says to it ‘Be!’ and it is (read fa-yakūnu, or fa-yakūna [in the subjunctive] on account of an implied [preceding] an). In other words, it comes into existence after He has willed it, that which is signified by the said words.
The Prohibition of Shirk, the Order for Tawhid, and the Evidence
Allah says, `say, O Muhammad, to these idolators, that Allah forbids them to worship anyone, such as these idols and false gods, except Him.' Allah explains that no one apart from Him is deserving of worship, as He says:
(It is He, Who has created you from dust, then from a Nutfah then from a clot (a piece of coagulated blood), then brings you forth as an infant, then (makes you grow) to reach the age of full strength, and afterwards to be old.) meaning, He is the One Who Alone, with no partner or associate, causes you to pass through these different stages, and this happens in accordance with His command, will and decree.
وَمِنكُمْ مَّن يُتَوَفَّى مِن قَبْلُ
(though some among you die before) means, before being fully formed and emerging to this world; so his mother miscarries him. And there are some who die in infancy or in their youth, or when they are adults but before they reach old age, as Allah says:
(And when He decides upon a thing He says to it only: "Be!'' -- and it is.) means, He cannot be opposed or resisted. Whatever He wills definitely comes to pass.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
That is, "Someone dies before birth, and someone before attaining youth, and someone before reaching old age. "
"An appropriate time" may either imply the time of death, or the time when all human beings will be resurrected and presented before their Lord. In the first case, the meaning would be: Allah passes every man through different stages of life and takes him to the specific time which He has appointed for everyone's return. Before that time even if the whole world joins to kill him, it cannot kill him; and when that time has arrived, none can keep him alive even if all the powers of the world join together to do so. In the second case, it would mean: This gamut of life has not been brought about so that man may end up in the dust and be completely annihilated, but Allah passes him through different stages of life so that all human beings may present themselves before Him at the time which He has appointed for the purpose.
That is, "You are not being passed through these different stages of lift so that you may live as the animals live and die as they die, but for the purpose that you may use yew common sense which Allah has granted you and thay understand the system in which you are living. The creation of a wonderful thing like life from the lifeless substances of the earth, then the coming into being of a marvelous creation like man from the microscopic germ of the sperm, then its developing inside the mother's womb, from the time of conception till delivery, in such a manner that its sex, its form and appearance, its bodily structure, its mental qualifies and characteristics, and its faculties and capabilities should be determined therein, un-influenced by any external factor or agency. Then the one who is to be eliminated by abortion does fall a prey to abortion, the one who is to die in infancy, does die in infancy, whether he be the child of a king, and the one who is to reach maturity or old age, does reach that age, even through highly dangerous conditions, in which death should be certain, and the one who is to die in a particular stage of life, does die in that stage even if he is given the best medical attention and treatment in the best hospitals by the best doctors. Are not all these things pointing to the truth that the ultimate control of life and death is in the hand of an all-Mighty Sovereign? And when the reality is this that an all-Powerful Being is controlling ow life and death, then how did a prophet or a saint or an angel or a star or planet become worthy of ow worship and service? When did a creature attain the rank that we should pray to it, and accept it as the maker and un-maker of our destiny? And how did a human power have the status that we should obey its commands and prohibitions and its self-made law about the lawful and the unlawful, without question? (For further explanation, see Al-Hay: 5-7 and the E.N.'s on it).