Whosoever introduces a good practice in Islam, there is for him its reward and the reward of those who act upon it after him without anything being diminished from their rewards. And whosoever introduces an evil practice in Islam will shoulder its sin and the sins of all those who will act upon it, without diminishing in any way their burden

This Hadīth shows the Prophet's care and compassion towards his followers. As the Companions were with the Prophet, early in the day, there came a group of people, mostly or entirely from Mudar tribe, wearing very simple clothes, which indicated their poverty, and hanging their swords, a sign of readiness to receive order for Jihād. The Prophet's face changed when he saw their poor state despite belonging to Mudar, one of the noblest Arab tribes. So, he entered home and then went out.

He ordered Bilāl to proclaim the Adhān and then he offered the prayer and addressed the people. Praising Allah, the Almighty, as usual, he recited the verses that reads: (O mankind, fear your Lord, who created you from one soul and created from it its mate and dispersed from both of them many men and women. And fear Allah, through whom you ask one another, and the wombs. Indeed Allah is ever, over you, an Observer) [Sūrat An-Nisā':1]; (O you who believe, fear Allah and keep your duty to Him.

And let every one look what he has sent forth for the tomorrow. Indeed, Allah is Acquainted with what you do) [Sūrat al-Hashr: 18]. Then, he encouraged the people to give charity, and in response they began to give, and a man would give his dinar in charity, another would give a dirham, and others would give their garment or a Sā‘ of wheat or dates. Then, he encouraged charity even if it were half a date.

The Companions (may Allah be pleased with them) were most keen on doing good, rushing and vying towards this. One of them came with a bundle that was almost too heavy for him to carry and placed it in front of the Prophet.

Seeing all this goodness and generosity, which would meet the need of those poor people, the Prophet (may Allah's peace and blessings be upon him) was very pleased, and he said: "Whosoever introduces a good practice in Islam, there is for him its reward and the reward of those who act upon it after him without anything being diminished from their rewards.

And whosoever introduces an evil practice in Islam will shoulder its sin and the sins of all those who will act upon it, without diminishing in any way their burden." "A good practice" here refers to something already established and rooted in the religion, not contrived and added to it.