The least you can do to help someone is keep them safe from your harm

I asked the Prophet ﷺ, “Which deed is best?” He said, “Belief in Allah and striving in His cause.” I said, “Then which slave is best to free?” He said, “The one with the highest price and the most valued by his people.” I said, “And if I cannot do that?” He said, “Help a craftsman, or do something for one who has poor judgement or is incompetent.” I said, “And if I cannot do that?” He said, “Keep people safe from your harm, for that is a charity you give on your own behalf.”

سَأَلْتُ النَّبِيَّ ﷺ أَىُّ الْعَمَلِ أَفْضَلُ؟ قَالَ: «إِيمَانٌ بِاللَّهِ، وَجِهَادٌ فِي سَبِيلِهِ» قُلْتُ: فَأَىُّ الرِّقَابِ أَفْضَلُ؟ قَالَ: «أَغْلاَهَا ثَمَنًا وَأَنْفَسُهَا عِنْدَ أَهْلِهَا» قُلْتُ: فَإِنْ لَمْ أَفْعَلْ؟ قَالَ: «تُعِينُ صَانِعًا أَوْ تَصْنَعُ لِأَخْرَقَ» قَالَ: فَإِنْ لَمْ أَفْعَلْ؟ قَالَ: «تَدَعُ النَّاسَ مِنَ الشَّرِّ فَإِنَّهَا صَدَقَةٌ تَصَدَّقُ بِهَا عَلَى نَفْسِكَ»

I said: Messenger of Allah, which of the deeds is the best? He (the Holy Prophet) replied: Belief in Allah and Jihad in His cause. I again asked: Who is the slave whose emancipation is the best? He (the Holy Prophet) replied: One who is valuable for his master and whose price is high. I said: If I can't afford to do it? He (the Holy Prophet) replied: Help an artisan or make anything for the unskilled (labourer). I (Abu Dharr) said: Messenger of Allah, you see that I am helpless in doing some of these deeds. He (the Holy Prophet) replied: Desist from doing mischief to the people. That is the charity of your person on your behalf.

قُلْتُ يَا رَسُولَ اللَّهِ أَىُّ الأَعْمَالِ أَفْضَلُ قَالَ الإِيمَانُ بِاللَّهِ وَالْجِهَادُ فِي سَبِيلِهِ قَالَ قُلْتُ أَىُّ الرِّقَابِ أَفْضَلُ قَالَ أَنْفَسُهَا عِنْدَ أَهْلِهَا وَأَكْثَرُهَا ثَمَنًا قَالَ قُلْتُ فَإِنْ لَمْ أَفْعَلْ قَالَ تُعِينُ صَانِعًا أَوْ تَصْنَعُ لأَخْرَقَ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ أَرَأَيْتَ إِنْ ضَعُفْتُ عَنْ بَعْضِ الْعَمَلِ قَالَ تَكُفُّ شَرَّكَ عَنِ النَّاسِ فَإِنَّهَا صَدَقَةٌ مِنْكَ عَلَى نَفْسِكَ