Richard Baxter, the famous practical divine of the 17th century, was a Puritan--of sorts. He was actually rather eclectic theologically, but excelled about everyday piety. Here (in truncated form) he summarizes important attitudes and piety of teachers.
I. Determine first rightly of your end...1. That your ultimate end be the pleasing and glorifying of God. 2. And this by promoting the public good, by fitting youth for public service. And, 3. Forming their minds to the love and service of their Maker. 4. And furthering their salvation, and their welfare in the world.
II. Understand the excellency of your calling, and what fair opportunities you have to promote those noble ends ; and also how great a charge you undertake; that so you may be kept from sloth and superficialness, and may be quickened to a diligent discharge of your undertaken trust.
III. Labour to take pleasure in your work, and make it as a recreation, and take heed of a weary or diverted mind. 1. To this end consider often what is said above; think on the excellency of your ends, and of the worth of souls, and of the greatness of your advantages. 2. Take all your scholars as committed to your charge by Jesus Christ; as if he had said to you, Take these whom I have so dearly bought, and train them up for my Church and service. 3. Remember what good one scholar may do, when he cometh to be ripe for the service of the Church or commonwealth! How many souls some of them may be the means to save! Or if they be but fitted for a private life, what blessings may they be to their families and neighbours!
IV. Seeing it is divinity that teacheth them the beginning and the end of all their other studies, let it never be omitted or slightly slubbered over, and thrust into a corner; but give it the precedency, and teach it them with greater care and diligence than any other part of learning: especially teach them the catechism and the Holy Scriptures. If you think that this is no part of your work, few wise men will choose such teachers for their children...Therefore teach them betimes the words of catechisms, and some chapters of the Bible; and teach them the meaning by degrees as they are capable. And make them perceive that you take this for the best of all their learning.
V. Besides the forms of catechism, which you teach them, speak often to them some serious words, about their souls and the life to come, in such a plain, familiar. manner, as tendeth most to the. awakening of their consciences, and making them perceive how greatly what you say concerneth them. A little such familiar serious discourse, in an interlocutory way, may go to their hearts, and never be forgotten; when mere forms alone are lifeless and unprofitable. Abundance of good might be done on children, if parents and schoolmasters did well perform their parts in this.
VI. Take strict account of their spending the Lord's day!—how they hear, and what they remember, and how they spend the rest of the day; for the right spending of that day is of great importance to their souls! And a custom of play and idleness on that day doth usually debauch them, and prepare them for much worse. Though they are from under your eye on the Lord's day, yet if on Monday they be called to account, it will leave an awe upon them in your absence.
VII. Pray with them and for them. If God give not the increase by the dews of heaven, and shine not on your labours, your planting and watering will be all in vain. Therefore prayer is as suitable a means as teaching, to do them good: and they must go together.
VIII. Watch over thom, by one another, when they are behind your backs, at their sports, or converse with each other; for it is abundance of wickedness that children use to learn and practise, which never cometh to their masters' ears, especially in some great and public schools.
IX. Correct them more sharply for sins against God, than for their dulness and failing at their books. Though negligence in their learning is not to be indulged, yet smart correction should teach them especially to take heed of sinning; that they may understand that sin is the greatest evil.
X. Especially curb or cashier the leaders of impiety and rebellion, who corrupt the rest. There are few great schools but have some that are notoriously debauched; that glory in their wickedness; that in filthy talking, and fighting, and cursing, and reviling words, are the infecters of the rest. And usually they are some of the bigger sort that are the greatest fighters, and master the rest, and by domineering over them, and abusing them, force them both to follow them in their sin and to conceal it. The correcting of such, or expelling them if incorrigible, is of great necessity to preserve the rest; for if they are suffered, the rest will be secretly infected and undone, before the master is aware. This causes many that have a care of their children's souls, to be very fearful of sending them to great and public schools, and rather choose private schools that are freer from that danger; it being almost of as great concernment to children, what their companions be as what their master is.
[The Nobler Exercises of His Profession, 1680]