If you love those who love you, what credit is that to you? For sinners do the same. Rather, love your enemies and do good to them, and lend to them expecting nothing in return. Then your reward will be great, and you will be sons of the Most High. Luke 6:32-35.

The Lord also teaches that a person cannot do good of himself which is real good, in John:

A person cannot take anything unless it is given him out of heaven. John 3:27.

And in another passage:

Jesus said, I am the vine, you are the branches. Just as the branch cannot bear fruit by itself, unless it remains on the vine, so neither can you unless you remain in me. He who remains in me, and I in him, bears much fruit. For you can do nothing except from me. John 15:4-8.