And my God will meet all your needs according to the riches of his glory in Christ Jesus. Philippians 4.19
In human terms self-sufficiency is an arrogant delusion. Nobody has it all. We are all lacking in some way or another and we do need each other, whether we choose to admit it or not. Yet there is a legitimate state of detachment, which develops as we wean ourselves off the need for affirmation and our thirst for vengeance. Jesus claims the right to judge and he teaches that we should give in secret, not letting our left hand know what our right hand is doing.
Giving without glory and leaving our desire to "get even" with God are liberating because they deliver us from the insecurity of depending on the approval of others and they free us from the cycle of retribution. They amount not to self-sufficiency but sufficiency in God. Fine exemplars of this state of being are to be found among our suffering sisters and brothers in places where it is illegal to follow Jesus and where believers are persecuted. Instead of desiring the removal of their tormentors, they invariably ask us to pray for their salvation!
Far from being no earthly good, being heavenly minded helps us to operate with pure hearts because we are able focus on the needs of others, our own having been invested in God.