To teach in order to lead others to faith is the task of every preacher and of each believer.
Thomas AquinasCommemoration of Gilbert of Sempringham, Founder of the Gilbertine Order, 1189 Some there are who presume so far on their wits that they think themselves capable of measuring the whole nature of things by their intellect, in that they esteem all things true which they see, and false which they see not. Accordingly, in order that man's mind might be freed from this presumption, and seek the truth humbly, it was necessary that certain things far surpassing his intellect should be proposed to man by God.
Thomas AquinasMan cannot live without joy; therefore when he is deprived of true spiritual joys it is necessary that he become addicted to carnal pleasures.
Thomas AquinasIt [covetousness] is a sin against God, just as all mortal sins, in as much as man condemns things eternal for the sake of temporal things.
Thomas AquinasIt 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 Aquinas