John Gill Commentary Luke 6:32

"And if ye love them that love you, what thank have ye? for even sinners love those that love them." — Luke 6:32 (ASV)

For if you love them which love you, what thank have you? &c.] Or, "what grace have you?" 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 you?" 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).