What should be the foremost concern of the professional teacher

Teaching is a tough gig, I have done it at various levels, it as been successful when I got the compliance o the pupils, but in the main it has been uphill,to say the least

 What should be the foremost concern of the professional teacher?

A teacher shall recognize that the interest and welfare of learners are of first and foremost concern, and shall deal justifiably and impartially with each of them.