No outward change need trouble him who is inwardly serene.
I'm very levelheaded.
If an individual has a calm state of mind, that person's attitudes and views will be calm and tranquil even in the presence of great agitation.
I've always been a level-headed guy.
I have my head screwed on right. I haven't been this way in a long time.
I tend to stay quite level. I make better decisions when I am level and I also take in good information when I am level, so it's important for me to stay in that head space.
The man who gives way to anger, or hatred, or any other passion, cannot work; he only breaks himself to pieces, and does nothing practical. It is the calm, forgiving, equable, well-balanced mind that does the greatest amount of work.
A pure, sincere, and stable spirit is not distracted though it be employed in many works; for that it works all to the honor of God, and inwardly being still and quiet, seeks not itself in any thing it doth.