Ecclesiastes 8:12 Though a sinner do evil an hundred times, and his days be prolonged, yet surely I know it shall be well with them that fear God, which fear before him.
The conditional promise is this: if you fear God (believe Him), then it will be well with you. The hymn writer could sing, “It is well with my soul,” even after the worst tragedy. No matter what, it will always be well with the one who has faith.
Yes, we faithful God-fearers who believe are at the same time, and all the time, failing sinners who “do evil a 100 times.” The simul justus et peccator person fails, repents, believes, is forgiven and is declared righteous. Sin brings him down; faith lifts him up, and so it goes on daily with a continual rhythm of daily repentance and renewal of faith, with dying daily in remembrance of Baptism and coming forth a new man, with willingness to be humbled and trusting to be raised up.
But it is, in the last analysis, the Gospel that has the last word: it will be well with you! We can live well with that faith, love, joy, peace, and hope. Only believe! We live, breathe, and walk under The Promise.