וַאֲנִ֤י אָמַ֙רְתִּי֙ לְרִ֣יק יָגַ֔עְתִּי לְתֹ֥הוּ וְהֶ֖בֶל כֹּחִ֣י כִלֵּ֑יתִי אָכֵן֙ מִשְׁפָּטִ֣י אֶת־יְהוָ֔ה וּפְעֻלָּתִ֖י אֶת־אֱלֹהָֽי׃
But I said: ‘I have laboured in vain, I have spent my strength for nought and vanity; Yet surely my right is with the LORD, And my recompense with my God.’
Read halakhic rulings (Jewish law) on Isaiah 49:4: and classical halakhic sources.