To be of good courage, to be cheered, to have one's spirit lifted. Literally 'to have a good soul' (eu + psyche). Paul uses this once, expressing his hope that good news about the Philippians will encourage him — eupsucheo — lift his soul while he sits in prison.
Eupsucheo reveals the mutual encouragement at the heart of Christian community. Paul, chained in prison, finds his soul lifted not by his own circumstances improving but by hearing of others' faithfulness (Philippians 2:19). The Christian is never a lone soul — we are bound together so that one person's faithfulness becomes another's encouragement. This is the body of Christ in action.