Meaning of “And of everything, We have created pairs…”
Question

My question is about the verse “And of everything We have created pairs, that you may remember” [adh-Dhariyat 51:49]
Does the word pairs [zawjayn] include two variations of the same thing, such as apples for example?
Does the word “pairs” occur in the same context in all the verses which speak of the creation of everything in pairs? Can you give some examples of the usage of this word, along with evidence?
Praise be to Allah.Meaning of “And of everything We have created pairs…”
Allah, may He be glorified and exalted, says (interpretation of the meaning): “And of everything We have created pairs, that you may remember.” [adh-Dhariyat 51:49]
What the verse means is that Allah, may He be exalted, has created pairs of all created things; that is, two opposite types or counterparts, such as male and female, night and day, heat and cold, and so on. This is indicative of the perfect might of Allah, may He be exalted, Who creates whatever He wills. So He creates a thing and He creates its opposite, which differs from it in its characteristics.
At-Tabari (may Allah have mercy on him) said:
"There was a difference of opinion concerning the words “We have created pairs”. Some scholars said that what is meant by it is: We have created two different types of everything, such as misery and happiness, guidance and misguidance, and so on.
Mujahid said: Disbelief and faith, misery and happiness, guidance and misguidance, night and day, heaven and earth, and male and female.
Others said: What is meant by pairs is male and female.
The view that is more likely to be correct is the view of Mujahid, which is that for everything that Allah, may He be blessed and exalted, created, He created a counterpart to it that is different from it in some senses, so that each is an opposite or counterpart of the other. Hence He said “We have created pairs”. In these words, Allah is drawing attention to His might and power to create whatever He wills, and that He is not like created beings which do one type of action and do not do the counterpart thereof, because anything that can do one thing but not the other – such as fire, which can only heat and cannot cool, or ice, which can only cool and cannot heat – cannot be described as perfect; rather perfect and utmost praise is due only to the One Who is able to do all that He wills of things that are different or similar.” (Tafsir at-Tabari (22/439-440)
Ibn Kathir (may Allah have mercy on him) said:
“And of everything We have created pairs, that you may remember” [adh-Dhariyat 51:47] means: all things are created in pairs: heaven and earth, night and day, sun and moon, land and sea, light and darkness, faith and disbelief, death and life, misery and happiness, Paradise and Hell, and even animate beings – jinn and humans, male and female – and plants. Hence Allah says: “that you may remember” that is, so that you may know that the Creator is one, with no partner or associate.” (Tafsir Ibn Kathir (7/424)
Al-Qurtubi (may Allah have mercy on him) said:
“The words “And of everything We have created pairs” means of two types, and two different varieties. Ibn Zayd said: That is, male and female, sweet and sour, and so on. Mujahid said: That is, male and female, heaven and earth, sun and moon, night and day, light and darkness, plains and mountains, jinn and humans, good and evil, morning and evening, and different types of things, such as tastes, smells and sounds. In other words, We have made this like that as an indication of Our might, for the One Who is able to do that is able to recreate [all of that, on the Day of Resurrection].” (Tafsir al-Qurtubi (17/53)
Ibn Jizzi (may Allah have mercy on him) said:
“That is, to different types, such as night and day, black and white, health and sickness, and so on.” (Tafsir Ibn Jizzi, 2/310)
Meaning of “and of every fruit He has placed therein two kinds”
With regard to the verse in which Allah, may He be exalted, says (interpretation of the meaning): “and of every fruit He has placed therein two kinds [zawjayn],” [ar-Ra‘d 13:3], Ibn Kathir said: “That is, of everything [He has made] two types.” (Tafsir Ibn Kathir, 4/431)
Al-Qurtubi said:
“That is, two types. Abu ‘Ubaydah said: The word zawj may refer to one or two.
And it was said that what is meant by zawjayn is two types, such as sweet and sour, fresh and dry, white and black, small and large.” (Tafseer al-Qurtubi, 9/280)
Ibn ‘Atiyah (may Allah have mercy on him) said:
“Zawj in this verse refers to type or kind… Other examples include the following verses (interpretation of the meaning):
“Exalted is He who created all pairs - from what the earth grows and from themselves and from that which they do not know.” [Ya-Sin 36:36]
“And the earth - We spread it out and cast therein firmly set mountains and made grow therein [something] of every beautiful kind.” [Qaf 50:7]
This verse implies that every fruit has two types, and if there are more than two types of a particular fruit, that does not change the meaning of the verse.… It may be said that of every fruit there is male and female.” (Tafsir Ibn ‘Atiyah, 3/293)
And Allah, may He be exalted, says (interpretation of the meaning):
“And the earth - We spread it out and cast therein firmly set mountains and made grow therein [something] of every beautiful kind.” [Qaf 50:7]
Ibn Kathir said: “That is, of all crops, fruits, plants and types.” (Tafsir Ibn Kathir, 7/396)
As-Sa‘di (may Allah have mercy on him) said: “That is, every kind of plant that is pleasant to the eye and brings delight and joy to the observer, as food for the sons of Adam and their livestock, and bringing other benefits.” (Tafsir as-Sa‘di, p. 804)
What is the meaning of zawj and zawjayn? 
So zawj means type, and zawjayn means a pair of opposite types or counterparts, such as sweet and sour, fresh and salt [referring to water]. Apples are one type, oranges are another type, and each type has its own taste and colour.
Or there may be a pair of one type, such as oranges, apples, dates and grapes, among which are male and female, small and large, and different types of colours and tastes.
Meaning of verses like “And We created you in pairs”
With regard to the verse in which Allah, may He be exalted, says: “And We created you in pairs” [an-Naba 78:8], it is like the verses in which He, may He be glorified and exalted, says:
“And Allah has made for you wives [azwaj] of your own kind.” [an-Nahl 16:72]
“Allah created you from dust, then from a drop of semen, then He made you pairs [male and female].” [Fatir 35:11]
“He has given you spouses [azwaj] of your own kind.” [ash-Shura 42:11]
This is addressed to the children of Adam, and what is meant is: We have created you, males and females, from one type, so that each of them may find comfort in the other, so that there may be affection and compassion, which will result in offspring. (Tafsir Ibn Kathir, 8/302) and Tafsir as-Sa‘di, p. 906)
For more about the issues related to creation, please see these answers: 13379 , 13286 and 6543 .
And Allah knows best.