Allah The Almighty Says (what means): {Mothers may breastfeed their children two complete years for whoever wishes to complete the nursing [period]. Upon the father is the mothers' provision and their clothing according to what is acceptable. No person is charged with more than his capacity. No mother should be harmed through her child, and no father through his child. And upon the [father's] heir is [a duty] like that [of the father]. And if they both desire weaning through mutual consent from both of them and consultation, there is no blame upon either of them. And if you wish to have your children nursed by a substitute, there is no blame upon you as long as you give payment according to what is acceptable. And fear Allah and know that Allah is Seeing of what you do.} [Quran 2:233]

　　Opinions of Scholars of Tafseer

　　Referring to the aforementioned verse, Ibn Katheer commented: "It is a guidance for mothers to breastfeed their children the complete term of two years.”

　　However, the rules of suckling, specifically the one related to marriage, do not apply to a child who is nursed beyond this period. Most leading scholars are of the opinion that suckling a baby who is less than two years old establishes relations with him or her that prohibit marriage, which is not the case if he or she is nursed beyond that age. At-Tirmithi assigned a chapter in his book Sunan to this very issue, in which he reported that Umm Salamah, may Allah be pleased with her, narrated that the Prophet, , said, "Suckling does not prohibit [marriage], except when it penetrates the intestines [serving as nourishment for the child] from the breasts, and it is prior to weaning."

　　“From the breasts” indicates the occurrence of breastfeeding to be within two years, as the term was also used by the Prophet, , who said, "My son Ibraheem died [when he was still feeding] from the breasts. He has two wet nurses in Paradise who will suckle him the complete term."[Muslim] In another version: "He has a wet nurse in Paradise."[Al-Bukhari] The Prophet, , said this because his son Ibraheem died when he was one year and ten months old.

　　Accordingly, most scholars believe the prohibition of marriage due to suckling, for infants less than two years to be a practice from among the Companions of the Prophet, , and others. Among them are ‘Ali, Ibn ‘Abbaas, Ibn Mas‘ood, Jaabir, Abu Hurayrah, Ibn ‘Umar, Ibn Salamah, may Allah be pleased with them, Sa‘eed ibn Al-Musayyib and ‘Ataa' .

　　The same opinion is also narrated on the authority of the majority of scholars. Al-Qurtubi said that the two years in the above mentioned verse are qualified to be the complete period of suckling. Other scholars, as well as followers of the opinion of Imam Maalik who cited that in his Muwatta’, also inferred from the above verse that suckling which, in effect, enforces what are similar to blood relations, thereby prohibiting marriage, is only what is done when the child is less than two years of age.

　　Shu‘bah narrated from ‘Amr ibn Dinaar who authentically narrated from Ibn ‘Abbaas, may Allah be pleased with him, that the Prophet, , said, "Suckling which prohibits marriage is that which is done within two years."

　　In his book of Tafseer (interpretation of the Quran), Ar-Raazi said, "Specifying the term of breastfeeding to be two years indicates a special ruling in Sharee’ah, which is the saying of the Prophet 'Suckling prohibits what blood relations prohibit.'”

　　Ash-Shawkaani in his Tafseer, says, "The verse also proves that it is not obligatory to breastfeed the baby for two years. To do so would be an act of perfection, but it is permissible to nurse for less."

　　Rationale behind the period of two years

　　Hence, the Sharee’ah shows that breastfeeding is what is done within two years. But, is there any medical wisdom behind it?

　　The Nelson Essentials of Pediatrics, a famous reference on children's medicine, published in 1994, touched upon this issue, citing the findings of modern researches that showed a strong link between the number of times and the period of breastfeeding and the incidence of type-1 diabetes. This was based on some relevant studies carried out on children in Norway, Sweden and Denmark.

　　Researchers explained this discovery with the fact that the mother's milk protects the baby against environmental factors that destroy pancreatic beta cells in children who are genetically prone to developing diabetes. On the other hand, artificial baby formula and foods, and even cow’s milk, contain chemical elements that may poison those cells. These findings were not particular to these nations, as it was also observed in other countries that the period of breastfeeding is inversely proportional to the occurrence of diabetes. Therefore, researchers recommend mothers to nurse for an extended time, to safeguard children from this disease and maintain their overall health in the future.

　　In fact, a recently developed theory suggests that cows' milk protein could lead to an otherwise preventable biological reaction that results in the destruction of pancreatic cells that produce insulin. In support of this theory, it was found that there are high rates of antibodies to cows' milk proteins in the serum of diabetic children compared to non-diabetics.

　　In a study, which was published in the January issue of Diabetes Digest in 1998, researchers discovered that cow's milk protein is an independent element that causes diabetes in some children, irrespective of hereditary factors. The same journal had earlier established the existence of a strong relation between ingesting artificial formula and products containing cows' milk particularly in the first year of a baby’s life, and the development of diabetes.

　　A month later, in February 1998, another study was published in the Immunity journal, which revealed that researchers concluded that feeding cows' milk and some other artificial baby formula as substitutes for mothers' milk led many nine-month-old infants to develop diabetes. Therefore, they recommended long periods of natural breastfeeding.

　　Further, under my personal supervision, a study was conducted in the Gastroenterology Department in 1995, in which we discovered that antibodies to cows' milk were found in the serum of children who were fed that until they were two years old. However, those who had cows' milk after the second year were free of these antibodies. This clearly proves the rationale behind the Quranic specification of breastfeeding for two complete years.

　　However, the question arises: Why does cow's milk cause this harm before the second year, but not after?

　　The journal Autoimmunity cited a study carried out in Finland in 1994, which explained that cows' milk protein passes intact through the membrane of the digestive tract. Enzymes in the digestive system cannot break the protein into amino acids. Consequently, cows' milk protein enters as a compound protein that stimulates the formation of immune bodies.

　　Similarly, modern references mention that the workings of the enzymes, the digestive system and its lining membrane, as well as the dynamics of digestion and absorption do not perfectly develop in the first months after birth. The development is gradually completed by the end of the second year.

　　All the above researches propose that if natural breastfeeding is done for nearly two years, immune bodies which are harmful to the pancreas beta cells that produce insulin, are less concentrated. On the other hand, if alternative feeding, especially with cows' milk, begins early after birth, the concentration of the harmful immune bodies in the serum of the children increases.

　　Hence, it is no less than an accurate scientific direction, which we find in the Quran that specifies the period of breastfeeding to last nearly two years, as Allah The Almighty Says (what means): {And We have enjoined upon man [care] for his parents. His mother carried him, [increasing her] in weakness upon weakness, and his weaning is in two years.} [Quran 31:15] In another verse, He Says (what means): {and his gestation and weaning [period] is thirty months.} [Quran 46:15]

　　However, both these verses indicate that breastfeeding for two complete years is not obligatory, rather an act of perfection. The permissibility of nursing them for less than two years, as relevant Sharee‘ah rulings state, is derived from the part of the verse (what means): {And if they both desire weaning through mutual consent from both of them and consultation, there is no blame upon either of them.} [Quran 2:233]

　　Ibn Katheer says, "If the child's parents agree to wean him/her before two years after discussing it, then there is no blame on them. However, it is understood that an individual decision is not enough, and neither has the prerogative of exclusively taking that decision without consulting the other partner, as mentioned by Ath-Thawri and others. This indicates care for children and consideration for their welfare. Indeed, it is an aspect of the mercy of Allah The Almighty toward His servants that He has set rules for raising children and guided parents to [act for] the good of their children."

　　It is now very evident why breastfeeding is to be done for two complete years, as illustrated in the Quran. Modern science has further highlighted the miraculous recommendation of the Quran regarding this matter, that was revealed more than one thousand four hundred years ago. Allah The Almighty Says (what means): {We will show them Our signs in the horizons and within themselves until it becomes clear to them that it is the truth. But is it not sufficient concerning your Lord that He is, over all things, a Witness?} [Quran 41:53]