Ruling on collecting donations during the Jumu’ah khutbah
Question

What is the ruling on collecting donations during the second Jumu’ah khutbah, when the khateeb calls for that? What is the ruling on doing that at the time of the du’aa’ in the second khutbah? Is Jumu’ah prayer invalidated by giving donations during the khutbah? Is the Jumu’ah prayer of those who go among the rows to collect donations invalidated?.
Praise be to Allah.Firstly: 
Those who attend Friday prayers should focus fully on the khutbah. It is not permissible to be distracted from it, whether by returning a greeting or denouncing one who talks during the khutbah. 
It was narrated that Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “Whoever does wudoo’ and does wudoo’ well, then comes to Jumu’ah and listens attentively, will be forgiven (his sins) between that and (the next) Jumu’ah, and three days in addition to that, but whoever touches the pebbles has engaged in an idle action.” Narrated by Muslim (875). 
Al-Nawawi (may Allah have mercy on him) said:
 The words of the Prophet (peace and blessings of Allah be upon him), “but whoever touches the pebbles has engaged in an idle action” show that touching the pebbles and other kinds of fidgeting during the khutbah are forbidden. This indicates that the heart should be focused fully on the khutbah. What is meant by idle action is false and blameworthy things."(Sharh Muslim  6/147) 
Shaykh Saalih al-Fawzaan (may Allah preserve him) said: 
It is not permissible to fidget during the khutbah with one’s hand, foot, beard, garment or anything else, because the Prophet (peace and blessings of Allah be upon him) said: “but whoever touches the pebbles has engaged in an idle action.” According to another hadeeth: “Whoever engages in idle actions or steps over the people’s necks, it is Zuhr prayer for him.” Because fidgeting prevents khushoo’ (proper focus and humility). Similarly, it is not appropriate for him to turn to his right or left, or be distracted by looking at the people, and so on, because that distracts him from listening to the khutbah. Rather he should face towards the khateeb as the Sahaabah (may Allah be pleased with them) used to face towards the Prophet (peace and blessings of Allah be upon him) during the khutbah."(Al-Mulakhkhas al-Fiqhi 1/176). 
Collecting donations from the people who are attending the Jumu’ah khutbah distracts them greatly from the khutbah. It causes movement on the part of the one collecting the donations and the people who are giving them, and it involves the collector stepping over the necks of people. All of that is forbidden and goes against the purpose of Jumu’ah and the khutbah. This is not necessary, because donations can be delayed until after the prayer has ended. The one who does that is deprived of the reward of Jumu’ah and it is merely Zuhr for him. 
It was narrated from ‘Abd-Allah ibn ‘Amr ibn al-‘Aas (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “Whoever does ghusl on Friday and puts on some of his wife’s perfume, if she has any, and puts on his best clothes then does not step over the people’s necks and does not engage in idle actions during the exhortation, that will be an expiation for whatever comes between them (two Fridays). But the one who engages in idle actions and steps over the people’s necks, it will be Zuhr for him.” Narrated by Abu Dawood (347); classed as hasan by al-Albaani in Saheeh al-Targheeb (721). i.e., it will be like Zuhr in reward, and because of his idle actions and stepping over people’s necks, he will be deprived of the great reward which is attained by the one who prays Jumu’ah. ‘Awn al-Ma’bood. 
Shaykh al-Fawzaan (may Allah preserve him) said: 
It is not permissible for the one who is listening to the khutbah to give charity to a beggar during the khutbah, because the beggar has done something that it is not permissible for him to do, so he should not help him in doing something that is not permissible, which is speaking during the khutbah."(Al-Mulakhkhas al-Fiqhi  1/175). 
Secondly: 
The prohibition on speaking or playing with the pebbles etc applies equally both at the beginning of the khutbah and during the du’aa’. What some of the fuqaha’ said about it being permissible to speak during the du’aa’ is a weak view. 
Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allah have mercy on him) said:  
Some of the fuqaha’ (may Allah have mercy on them) said that when the imam starts to say du’aa’ during the khutbah, it is permissible to speak, because the du’aa’ is not one of the pillars (essential parts) of the khutbah, and speaking during something that is not one of the pillars of the khutbah is permissible. But this is a weak view, because so long as the du’aa’ is connected to the khutbah it is part of it. It was narrated that the Prophet (peace and blessings of Allah be upon him) used to pray for forgiveness for the believers every Friday during the khutbah. 
The correct view is that so long as the imam is speaking, whether it is the essential parts of the khutbah or what comes after it, speaking is haram."(Al-Sharh al-Mumti’  5/110). 
And Allah knows best.