Lukas 3:9

3:9 Even now the ax is laid at the root of the trees, ¹  and every tree that does not produce good fruit will be ²  cut down and thrown into the fire.”

Lukas 23:31

23:31 For if such things are done ³  when the wood is green, what will happen when it is dry?” ⁴ 

[3:9]  ¹ sn Even now the ax is laid at the root of the trees. The imagery of an “ax already laid at the root of the trees” is vivid, connoting sudden and catastrophic judgment for the unrepentant and unfruitful. The image of “fire” serves to further heighten the intensity of the judgment referred to. It is John’s way of summoning all people to return to God with all their heart and avoid his unquenchable wrath soon to be poured out. John’s language and imagery is probably ultimately drawn from the OT where Israel is referred to as a fruitless vine (Hos 10:1-2; Jer 2:21-22) and the image of an “ax” is used to indicate God’s judgment (Ps 74:5-6; Jer 46:22).

[3:9]  ² tn Grk “is”; the present tense (ἐκκόπτεται, ekkoptetai) has futuristic force here.

[23:31]  ³ tn Grk “if they do such things.” The plural subject here is indefinite, so the active voice has been translated as a passive (see ExSyn 402).

[23:31]  ⁴ sn The figure of the green wood and the dry has been variously understood. Most likely the picture compares the judgment on Jesus as the green (living) wood to the worse judgment that will surely come for the dry (dead) wood of the nation.