Answered by: Alimah Siddiqa al-Farsiyyah
someone wants to do wajib Qurbani so I help him by doing it through Ummah Welfare Trust. The price of one animal is £75 so I paid using my money first then asked him to pay the amount afterwards. The question is, is it permissible if I tell him to give me just £70 and I pay £5 for him out of Ihsan (for example)?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
In the Sharī’ah, there are three types of worship: 1. monetary worship such as Zakāh, 2. physical worship such as Ṣalāh, and 3. a combination of monetary and physical worship such as Ḥajj.
Performing Qurbānī is a monetary form of worship, in which delegation is permissible. Thus, it is permissible for one to purchase a Qurbānī on someone else’s behalf, and this absolves the person for whom the Qurbānī was purchased, from the obligation of performing Qurbānī themselves.
With regards to your question, although you do intend on giving the full price, you are still fulfilling a portion of their obligation through the payment of a portion of their wealth. As such, you may pay the £5 on their behalf. However, the precautionary measure is for you to do this with the acknowledgement of the person, as this is a condition set by Imam Abu Hanifah (may Allāh have mercy on him).
Only Allāh Ta’ālā knows best
Answered by Alimah Siddiqa al-Farsiyyah
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Al-Kāsānī, Badā’i us-Sanā’i, 2/212, DKI
أَنَّ الْعِبَادَاتِ فِي الشَّرْعِ أَنْوَاعٌ ثَلَاثَةٌ:مَالِيَّةٌ مَحْضَةٌ: كَالزَّكَاةِ وَالصَّدَقَاتِ وَالْكَفَّارَاتِ وَالْعُشُورِ وَبَدَنِيَّةٌ مَحْضَةٌ: كَالصَّلَاةِ وَالصَّوْمِ وَالْجِهَادِ.وَمُشْتَمِلَةٌ عَلَى الْبَدَنِ وَالْمَالِ: كَالْحَجِّ، فَالْمَالِيَّةُالْمَحْضَةُ تَجُوزُ فِيهَا النِّيَابَةُ عَلَى الْإِطْلَاقِ
 Al-Fatāwā al-Hindiyyah, 5/339, Al-Maktabah al-Faisal
وَمِنْهَا أَنَّهُ تَجْرِي فِيهَا النِّيَابَةُ فَيَجُوزُ لِلْإِنْسَانِ أَنْ يُضَحِّيَ بِنَفْسِهِ أَوْ بِغَيْرِهِ بِإِذْنِهِ؛ لِأَنَّهَا قُرْبَةٌ تَتَعَلَّقُ بِالْمَالِ فَتَجْرِي فِيهَا النِّيَابَةُ
 Fatāwā Qādhī Khān, 3/243, Al-Maktabah al-Faisal
ليس على الرجل أن يضحي عن أولاده الكبار و امرأته إلا بإذنهم و عن أبي يوسف رحمه الله تعالى أنه يجوز بغير أمرهم استحسانا