{Prepare for them whatever you are able of power} (89). This means that this is among the power that one is able to muster, so it enters under the general meaning of the verse.
1777 - Issue: He said: "And it is not permissible when the horses are sent off for one of the two to bring alongside his horse another horse to urge it to run, [nor to shout at it at the time] (1) of its race; because of what was narrated from the Prophet, peace and blessings of Allah be upon him, that he said: 'There shall be no janab and no jalab.'"
The meaning of al-janab is for the competitor to bring alongside his horse another horse without a rider to urge the one (2) beneath him to gallop and incite it to do so. This is the apparent view of al-Khiraqi. The Qadi said: Its meaning is to bring a horse alongside so that he can switch to it at the finish line, because it is less fatigued and exhausted. Ibn al-Mundhir said: That is what was said, but I do not think this is correct; because the horse with which one competes (3) must be specified. If it is the one he switches from, then the race was not won with it, and if it is the one he switches to, then the competition was not performed with it throughout the entire course, and that is a condition of the race. Also, (4) whenever he needs to switch and occupy himself with it, he might be beaten because of his preoccupation, not because of the speed (5) of another. Furthermore, the objective is to know the gallop of the horse throughout the entire course, so if he only rides it at the end of the course, the objective is not achieved. As for al-jalab, it is for a man to follow his horse, running behind it, shouting at it, and yelling behind it, thereby urging it to gallop. This is how Malik (6) interpreted it. Qatada said: Jalab and Janab are in betting (6). It was narrated from Abu Ubayd as the opinion of Malik. It was also narrated from him that the meaning of al-jalab is for the tax collector to gather...
(89) Sūrat al-Anfāl 60. (1) In the original: "wa-lā yaṣiḥḥu bihi fī waqt". And in A: "wa-lā yaṣīḥu fī waqt". (2) In the original, M: "alladhī". (3) In M: "ʿalayhā". (4) Omitted from: B. (5) In M: "surʿa". (6) Both were mentioned by al-Bayhaqī, in: Bāb mā jāʾa fī al-rihān ʿalā al-khayl wa-mā yajūzu wa-mā lā yajūzu, from Kitāb al-Ramy. al-Sunan al-Kubrā 10/21, 22.