John Gill Commentary Luke 23:39

"And one of the malefactors that were hanged railed on him, saying, Art not thou the Christ? save thyself and us." — Luke 23:39 (ASV)

And one of the malefactors, which were hanged
On the cross, one of the thieves crucified with Christ; the Oriental versions add, "with him"; according to the Evangelists Matthew and Mark, both of them reviled him, and threw the same things in his teeth as the priests, people, and soldiers did; which how it may be reconciled, (See Gill on Matthew 27:44)

railed on him, saying, if you are Christ, save yourself, and us ;
taking up the words of the rulers, and adding to them, perhaps, with a design to curry favour with them, hoping thereby to get a release; or, however, showing the wickedness and malice of his heart, which his sufferings and punishment, he now endured, could make no alteration in; see (Revelation 16:9) .