Adam Clarke on Isaiah 49:16

Behold, I have graven thee upon the palms of my hands "Behold, on the palms of my hands have I delineated thee" - This is certainly an allusion to some practice, common among the Jews at that time, of making marks on their hands or arms by punctures on the skin, with some sort of sign or representation of the city or temple, to show their affection and zeal for it. They had a method of making such punctures indelible by fire, or by staining. See note on Isa 44:6 (note). It is well known, that the pilgrims at the holy sepulcher get themselves marked in this manner with what are called the ensigns of Jerusalem. See Maundrell, p. 75, where he tells us how it is performed: and this art is practiced by travelling Jews all over the world at this day.