John Gill Commentary Luke 3:8

"Bring forth therefore fruits worthy of repentance, and begin not to say within yourselves, We have Abraham to our father: for I say unto you, that God is able of these stones to raise up children unto Abraham." — Luke 3:8 (ASV)

Bring forth therefore fruits worthy of repentance
Or "meet" for it, such as will show it to be true and genuine: "and begin not to say within yourselves": in one of Beza's copies, and in another of Stephens's, it was read, "think not", as in (Matthew 3:9) . the sense is the same. The Vulgate Latin and Ethiopic versions, leave out the phrase, "within yourselves": what they are forbid to say follows,

we have Abraham to our father, for I say unto you, God is able of
these stones to raise up children unto Abraham ;
which need not be thought strange, when the creation of Adam out of the earth, and the production of such a numerous offspring, as the Israelites were, from Abraham and Sarah, when past all hope of children, and are signified by the rock and pit in (Isaiah 51:1Isaiah 51:2) are considered; (See Gill on Matthew 3:9).