"Care must be taken that our speech proceed not from evil passions, but from good motives;
for here it is that the devil is especially on the watch to
"If anyone takes heed to this, he will be mild, gentle, modest.
For in guarding his mouth, and restraining his tongue, and in not speaking before examining, pondering, and weigh his words--as to whether this should be said, that should be answered, or whether it be a suitable time for this remark--he certainly is practicing modesty, gentleness, patience.
So he will not burst out into speech through displeasure or anger, nor give sign of any passion in his words, nor proclaim that the flames of lust are burning in his language, or that the incentives of wrath are present
in what he says.
The snare of the enemy is our speech--but that itself is also just as much an enemy to us. Too often we say something that our foe takes hold of, and whereby he wounds us as though by our own sword. How far better it is to perish by the sword of others than by our own!"
St. Ambrose (340-397)
He found himself chosen to be bishop after mediating an argument between Arians and Catholic while being a catechumen.
He devoted himself to learning theology and was ordained a priest and consecrated a bishop on December 7th in Milan.
He's written books on scripture and the early church fathers, composed hymns, and is credited for being involved in the conversion of St. Augustine.
You can read more about St. Ambrose's writings here.