כֹּ֥ה אָמַ֖ר יְהוָ֣ה צְבָא֑וֹת שִׂ֥ימוּ לְבַבְכֶ֖ם עַל־דַּרְכֵיכֶֽם׃
Ainsi parle l’Éternel-Cebaot: "Appliquez votre attention à votre manière d’agir!
Mesillat Yesharim
The second: on the actions which he does, to determine if they are in the category of the good or the evil.
Mesillat Yesharim
This applies both to times when he is in the act of doing and when not in the act of doing.