Luke 6:32

For if ye love them which love you, what thank have ye?
&c.] Or, "what grace have ye?" this is no fruit, nor evidence of grace, nor any exercise of the true grace of love; nor is it any favour conferred upon the object loved, which deserves the respect shown, nor can any reward be expected for such treatment: and thus it is expressed in Matthew, "what reward have ye?" and the Arabic version renders it so here:

for sinners also love those who love them:
men that are destitute of the grace of God, profligate sinners, even the worst of them, such as publicans, do this; (See Gill on Matthew 5:46).