“cowardice [δειλια] would seem to be a sort of fearful yielding of the soul” (Theophrastus, Characters [371-287 BC])
Cowardice (δειλια) “is a disease graver than any that affects the body since it destroys the faculties [δυναμις] of the soul. Diseases of the body flourish but for a short time, but cowardice is an inbred evil, as closely inherent or more so than any part of the bodily system from the earliest years to extreme old age, unless it is healed by God. For all things are possible to Him” (Philo, On the Virtues, 26; 1st century AD).
“For God did not give us a spirit of cowardice (δειλια) but of power[δυναμις], love and self-control.
Therefore do not be ashamed of the testimony about our Lord, nor of me his prisoner, but share in suffering for the gospel by the power [δυναμις] of God, who saved us and called us to a holy calling, not because of our works but because of his own purpose and grace, which he gave us in Christ Jesus before the ages began, and which now has been manifested through the appearing of our Savior Christ Jesus, who abolished death and brought life and immortality to light through the gospel, for which I was appointed a preacher and apostle and teacher, which is why I suffer as I do. But I am not ashamed, for I know whom I have believed, and I am convinced that he is able to guard until that Day what has been entrusted to me. Follow the pattern of the sound words that you have heard from me, in the faith and love that are in Christ Jesus. By the Holy Spirit who dwells within us, guard the good deposit entrusted to you.” (Paul, 2 Timothy 1:7-14; 1st century AD [ESV, altered])