The majority of scholars among the companions, the followers, the generation after them, and the jurists who came subsequently held that zakah on merchandise is compulsory. Abu Dawud and alBaihaqi relate that Samurah ibn Jundub reported: “The Prophet, upon whom be peace, used to command us to pay sadaqah from [the goods] we had for sale.” Ad-Daraqutni and al-Baihaqi relate that Abu Zharr reported the Prophet, upon whom be peace, saying: “There is sadaqah on camels, sheep, cows, and house furniture.” Ash-Shaf’i, Ahmad, Abu ‘Ubaid, ad-Daraqutni, al-Baihaqi, and ‘Abd ur-Razzaq relate that Abu ‘Amr ibn Hammas reported from his father that he said: “I used to sell leather and containers. Once, ‘Umar ibn al-Khattab passed by me and said: ‘Pay the sadaqah due on your property.’ I said: ‘O Commander of the Faithful, it is just leather.’ He replied: ‘Evaluate it and then pay its due sadaqah.’ “
Commenting on its credentials, Ibn Quadmah says in alMughni that this is a kind of story which is well-known and indisputable. This might be a consensus of opinion.
On the other hand, the Zahiriyyah maintain that merchandise is not subject to zakah. They differ, says Ibn Rushd, because of their use of analogical reasoning to the obligation of zakah and because of their disagreement on the authenticity of Samurah’s and Abu Zharr’s reports.
However, the majority of jurists view merchandise as a property which increases in value. Hence, by analogy, it is similar to the three categories upon which zakah must be paid: plantations, cattle, and gold and silver.
It is stated in al-Mandr: “Most scholars agree that zakah is obligatory on merchandise even though there is no clear-cut ruling in the Qur’an or the sunnah on this issue. However, there are a number of reports that corroborate each other with regard to the evidence provided by [their] texts. Their rationale is that since merchandise is a form of cash, there is no difference between it and dinars or dirhams in terms of which it is valued. This means that the form of the nisab can alternate between value in the form of cash and that which is valued in the form of merchandise. If zakah had not been obligatory on merchandise, the rich – or most of them – would have converted their cash into merchandise for trading purposes, making sure that the nisab of gold and silver is never possessed by them for a year.”
The main consideration here is that by levying zakah on the rich, Allah the Exalted wants to help the poor and to promote the welfare of the people in general. For the rich, its benefit lies in cleansing their persons of stinginess – both in money and feelings. For the poor, its benefit lies in easing their circumstances. Zakah thus eliminates the causes of corruption which results from the increase of money in a few hands. It is this wisdom which the Qur’an refers to when it deals with the distribution of booty: “…that it becomes not a commodity between the rich among you” (al Hashr 7). Therefore, it is not reasonable to exempt businessmen from their societal obligations when they possess most of the nation’s wealth.