Proverbs 3:27

Do not withhold good from those to whom it is due,
when it is in your power to do it.
Break this into three parts. First, we are told not to withhold good. We tend the think that as long as we are not doing evil, then we are being good. But here we are commanded not to withhold good. Apparently, we are guilty of transgression simply by letting an opportunity to do good go by. We kill by not coming to someones aid. We steal by withholding a good deed.
Secondly, we are to do good to those for whom it is due. To whom do we owe good deeds? Sounds like a question once asked of Jesus: Who is my neighbor? If we follow Jesus answer to this question given in the parable of the Good Samaritan, we have to conclude that the person to whom it is due, is whatever person God places along our path. As soon as we try to determine who is worthy of receiving good, we get into trouble. For to judge anyone as unworthy of receiving good from us is to place ourselves in a position of higher value than a fellow human being. Only God can determine whom to withhold good.
Finally, there is the condition when it is in your power to do it. When is good in our power? This takes discernment. Doing good is always in our power, and it is always in our power to act in a good manner. Where some Christians get into trouble is not discerning what the good is that the other person needs and sometimes not discerning his own ability to meet those needs. We can enable others to maintain sinful patterns through our good intentions. We can also harm ourselves or our families in our unwise actions. Be ready to do good to anyone, but use wisdom, so that you are truly helping the person in need without bringing harm to others (such as your family members) who are innocent.