Adam Clarke on Luke 6:36

Be ye therefore merciful - Or, compassionate; οικτιρμονες, from οικτος, commiseration, which etymologists derive from εικω to give place, yield, because we readily concede those things which are necessary to them whom we commiserate. As God is ever disposed to give all necessary help and support to those who are miserable, so his followers, being influenced by the same spirit, are easy to be entreated, and are at all times ready to contribute to the uttermost of their power to relieve or remove the miseries of the distressed. A merciful or compassionate man easily forgets injuries; pardons them without being solicited; and does not permit repeated returns of ingratitude to deter him from doing good, even to the unthankful and the unholy. See on Mat 5:7 (note).