Sahih Bukhari Volume 4, Book 56, Hadith 2990

حَدَّثَناإِسْحَاقُ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ كُلُّ سُلاَمَى مِنَ النَّاسِ عَلَيْهِ صَدَقَةٌ كُلَّ يَوْمٍ تَطْلُعُ فِيهِ الشَّمْسُ، يَعْدِلُ بَيْنَ الاِثْنَيْنِ صَدَقَةٌ، وَيُعِينُ الرَّجُلَ عَلَى دَابَّتِهِ، فَيَحْمِلُ عَلَيْهَا، أَوْ يَرْفَعُ عَلَيْهَا مَتَاعَهُ صَدَقَةٌ، وَالْكَلِمَةُ الطَّيِّبَةُ صَدَقَةٌ، وَكُلُّ خَطْوَةٍ يَخْطُوهَا إِلَى الصَّلاَةِ صَدَقَةٌ، وَيُمِيطُ الأَذَى عَنِ الطَّرِيقِ صَدَقَةٌ ‏"

Narrated By Abu Huraira : Allah's Apostle said, "There is a (compulsory) Sadaqa (charity) to be given for every joint of the human body (as a sign of gratitude to Allah) everyday the sun rises. To judge justly between two persons is regarded as Sadaqa, and to help a man concerning his riding animal by helping him to ride it or by lifting his luggage on to it, is also regarded as Sadaqa, and (saying) a good word is also Sadaqa, and every step taken on one's way to offer the compulsory prayer (in the mosque) is also Sadaqa and to remove a harmful thing from the way is also Sadaqa."