First rough analysis
The hadith of Jabir says:
وَكَانَ لِي عَلَيْهِ دَيْنٌ فَقَضَانِي وَزَادَنِي.
He owed me some money and he repaid it to me and gave more than what was due to me.
(See for example: Sahih Muslim, Sahih al-Bukhari here and here)
The situation here is about a debt and certainly paying back a plus in such a case may arise a question on riba. Well the definitions of riba of the different scholars are different and maybe readings them could be misleading (I've checked for example this article -in Arabic- displaying definitions of the sunni four school of jurisprudence and fatwa islamweb #165161). Therefore it is important to know how riba -in the given case- was practiced before Islam and what exactly Islam forbade:
Riba originated among the people of the Jaahiliyyah; if a debt became due, they would say to him (the borrower): Give us one hundred (that is due, now), or increase it to one hundred and fifty (and pay later). Then when the one hundred and fifty became due, they would say: Give us one hundred and fifty (now), or increase it to two hundred (and pay later) -- and so on. (Source fatwa islamqa #129458)
So as we see here the case described above doesn't apply as the obligee or donor didn't ask the debtor for an extra or an additional payment. As here the debtor gave an extra without the donor even considering to ask for it.
Definitions of riba
Let's go back and check the definitions now that we have a bit information about the historical background and check the definition in general and for the case of debt in special:
In the fatwa linked above riba is defined as follows:
I the following I'll be translating from Arabic language as these translations are of my own take them carefully!
والربا في اصطلاح الفقهاء يقصد به: زيادة مخصوصة لأحد المتعاقدين خالية عما يقابلها من العوض. ...
And usury (riba) in the terminology of jurists means: a specific increase for one of the contracting parties free of the corresponding consideration or counter value. ...
ربا الديون: وهو الذي نزل القرآن بتحريمه، ومعناه: الزيادة في الدين مقابل الزيادة في الأجل. وهو الذي كان شائعاً في الجاهلية، وعادت إليه البنوك في واقعنا المعاصر، وهو أشهر أنواع الربا وأشدها قبحاً.
Riba on debts: It is the one who was revealed the Qur’an forbidding it, and its meaning: an increase in the debt in exchange for an increase in the term. It is what was common in the pre-Islamic era, and the banks returned to it in our contemporary reality, and it is the most famous and most ugly type of usury.
(Source fatwa islamweb #165161)
The Hanafi's defined it as follows:
هو الفضل الخالي عن العِوَض بمعيار شرعي بشروط لأحد المتعاقدينِ في المعاوضة (Source alukah)
It is the credit free of compensation according to a legal standard with conditions for one of the contracting parties in the netting or chargeback.
According the same article the Maliki's and Shafi'is defined it as:
هو عقد على عِوَض مخصوص، غير معلوم التماثل في معيار الشرع حالة العقد أو مع التأخير في البدلين أو أحدهما
It is a contract for a specific consideration, the similarity (occurrence?) is not known in the criterion of Sharia at the time of the contract or with a delay in the two alternatives (cases?) or one of them.
As for the Hanbali definition -according the same article- it is:
هو الزيادة في أشياء مخصوصة
It is the increase in special things
As you see most of these definitions need some additional information and details to be put in the right context and to be understood well.
Cases which look like riba, but are not
In fact our case is one of three cases on which there's one could say consensus or majority view saying it isn't riba these three cases are (Source of the information IslamOnline Article on halal riba -in Arabic-):
- Selling fruits that are still in trees (for example: rutub -fresh dates- for dates) for the price of mellowed fruits this based on ahadith such as for example in Sahih al-Bukhari and in Sahih Muslim. However the Hanafi's hold the position that this is not permissible
- The none requested addition in case of a debt. And the hadith we discuss here is an example for that and there are others like in Sahih Muslim and in Sahih al-Bukhari. This view is considered by a huge majority of scholars among them the four sunni Imams, among the sahabah 'Abdullah ibn 'Umar, among the tabi'iyn Sa'id ibn al-Mussayib, al-Hassan al-Basry, Az-Zuhri, Makhool, 'Amir a-Sha'aby, Qatadah, Ishaaq ibn Rahawayh and one of two statements of Ibraheem an-Nakha'i.
- Installment selling: Selling one piece for a higher price than one would sell a bunch of the same product. Based on literal the meaning of "But Allah has permitted trade and has forbidden interest." (2:275) however the Zaydi's and some other hold a different position based on the hadith mentioned in Sunan abi Dawod.
A deeper look in our hadith from commentaries and other resources
In his Nayl al-Awtar نيل الأوطار imam a-Shawkani discussed our hadith in a chapter on additional payment when the debtor is paying back his due and the prohibition on it if it was before the due date "باب جواز الزيادة عند الوفاء والنهي عنها قبله" (see here -in Arabic-). Considering this a gift. However as the title says this gift could be regarded as a bribe if it was given before the payment of the debt itself. This chapter includes many similar narration. He also discussed the case if this gift would be a cause of a benefit which also falls in the case of bribery or alike and is discouraged in the sunnah.
In his al-Muhalla ibn Hazm also explicitly regards the opposite case of a donor who allows his debtor to pay less than the original debt as permissible.:
1193 - مَسْأَلَةٌ - فَإِنْ تَطَوَّعَ عِنْدَ قَضَاءِ مَا عَلَيْهِ بِأَنْ يُعْطِيَ أَكْثَرَ مِمَّا أَخَذَ، أَوْ أَقَلَّ مِمَّا أَخَذَ، أَوْ أَجْوَدَ مِمَّا أَخَذَ، أَوْ أَدْنَى مِمَّا أَخَذَ، فَكُلُّ ذَلِكَ حَسَنٌ مُسْتَحَبٌّ. (Source)
Case - if the volunteer when spending what it gives to more than taking, or less than taking, or making the finest taking, or lower than taking, all of that good is desirable.
- Ibn Rajab in his fath al-Bary -see here- comment in the section about "Chapter: To offer As-Salat (the prayer) whe returning from a journey" quoted a longer vesrion of the hadith:
Jabir b. 'Abdullah (Allah be pleased with them) reported:
Allah's Messenger (ﷺ) bought a camel from me for two 'uqiyas and a dirham or two dirhams. As he reached Sirar (a village near Medina), he commanded a cow to be slaughtered and it was slaughtered, and they ate of that, and as he (the Holy Prophet) reached Medina he ordered me to go to the mosque and offer two rak'ahs of prayer, and he measured for me the price of the camel and even made an excess payment to me.
(See in Sahih al-Bukhari and Sahih Muslim)
This already excludes the option that the "money" as translated in your translation of the hadith was of gold or silver, but in more general meaning a wealth. And therefore the discussion of an exchange of gold by gold, silver by silver etc. doesn't apply here.
So we come to the conclusion that one could safely say none of the ahadith troubling you applies here.
- In the corresponding comment in 'Umdath al-Qari of al-'Ayni -see here in Arabic-, imam an-Nawawi was quoted saying:
وقال النووي : هذه الصلاة مقصودة للقدوم من السفر لا أنها تحية المسجد ، وفيه استحباب قضاء الدين زائدا ، وهو من باب المروءة ، وسيجيء فوائد هذا الحديث في موضعه إن شاء الله تعالى .
Al-Nawawi said: This prayer is intended for coming from travel, not because it is greeting the mosque, and it is desirable to pay off debts with an addition, and it is a matter of chivalry, and the benefits of this hadith will come in its place, God Almighty willing.
- Ibn Hajar when discussing our hadith in his fath al-Bary referred to his commentary on the hadith in which he summarized saying:
وفيه جواز الزيادة في الثمن عند الأداء ، والرجحان في الوزن لكن برضا المالك ، وهي هبة مستأنفة حتى لو ردت السلعة بعيب مثلا لم يجب ردها ، أو هي تابعة للثمن حتى ترد ، فيه احتمال .
It includes the permissibility of an increase in the price upon payment, and the weight is likely to be higher, but with the consent of the owner, and it is a resumed gift even if the commodity is returned with a defect, for example, it does not have to be returned, or it is dependent on the price until it is returned, there is a possibility.
So this addition to the payment of the debt is not regarded as riba rather than a gift under the given conditions.