It is altogether unlawful to kill oneself... Wherefore suicide is contrary to the inclination of nature, and to charity whereby every man should love himself... Life is God's gift to man, and is subject to His power, Who kills and makes to live. Hence whoever takes his own life, sins against God... for it belongs to God alone to pronounce sentence of death and life.
Thomas AquinasLikewise grace and glory are referred to the same genus, since grace is nothing other than a certain first beginning of glory in us.
Thomas AquinasIf a man deliberately abstains from wine to such an extent that he does serious harm to his nature, he will not be free from blame.
Thomas Aquinas