Two Old Testament reprobates kneel trembling in stable (2,2,4,4)
I believe the answer is:
on an even keel
'trembling in stable' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'two old testament reprobates kneel' is the wordplay.
I cannot really see how this works, but
'old' could be 'o' (abbreviation) and 'o' is located in the answer.
an anagram of 'kneel' is 'nkeel' which is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for on an even keel that I've seen before include "(Going) calmly" , "In a stable condition" , "Running smoothly" , "Well-balanced" , "Steady" .)