Teaching us, that, denying, etc. - Παιδευουσα· Instructing us as children are instructed. Christ is the great teacher; and men, in order to learn, must become his disciples - must put themselves under his tuition, and learn of him.
Denying ungodliness - Ασεβειαν· All things contrary to God; whatever would lead us to doubt his being, deny any of his essential attributes; his providence or government of the world, and his influence on the souls of men. Every thing, also, which is opposed to his true worship; theoretical and practical atheism, deism, and irreligion in general.
Worldly lusts - Such desires, affections, and appetites, as men are governed by who have their portion in this life, and live without God in the world. Gluttony, drunkenness, lasciviousness, anger, malice, and revenge; together with the immoderate love of riches, power, and fame.
We should live soberly - Having every temper, appetite, and desire, under the government of reason, and reason itself under the government of the Spirit of God.
Righteously - Rendering to every man his due, injuring no person in his body, mind, reputation, or property; doing unto all as we would they should do to us; and filling up the duties of the particular stations in which it has pleased God to fix us, committing no sin, omitting no duty.
And godly - Ευσεβως . Just the reverse of what is implied in ungodliness. See above.
In this present world - Not supposing that any thing will be purified in the world to come that is not cleansed in this. The three words above evidently include our duty to God, to our neighbor, and to ourselves.