A slightly more literal translation is provided by the BLB of 2 Tim 1:18 of its first sentence-
May the Lord grant unto him to find mercy from the Lord in that day!
In trying to understand this verse we should observe the following:
- In most (not all) cases "the Lord" in the NT is Jesus and the context here suggests nothing to alter this general trend. This is especially true when "Lord" is used as a stand-alone noun (as distinct from "Lord God", etc.)
- "day of the Lord" and "that day" are NT technical phrases for the second coming of Jesus, eg, 2 Peter 3:10, 12, 1 Thess 5:2, 4, 2 Thess 2;2, 1 Cor 3:13, 5:5, 2 Cor 1:14, Acts 2:20, Heb 10:25, etc, etc.
The Pulpit commentary suggests this:
The repetition of "the Lord" is remarkable, but nothing seems to hang
upon it. The second παρὰ Κυίου seems to suppose the Lord sitting on
the judgment throne.
Ellicott offers a further note:
Some commentators, who have found a difficulty in this unusual
repetition of “the Lord,” explain it thus: The expression, “the Lord
grant,” had become among Christians so completely “a formulary,” that
the second use of the word “Lord” was not noticed; and the prayer is
thus-simply equivalent to “O that he may find mercy of the Lord.”