Chapter 155
Do Not Withdraw Your Attention From the Lord
I hasten to tell you a word or two. Distraction. This is the first hostile attack against the inner order from the enemy. Take care that when you enter into contact with others and busy yourself with affairs, you remember the Lord at the same time, and do and speak everything with the awareness that the Lord is near, directing all things toward pleasing Him. To this end, when something happens, prepare yourself beforehand during the matter not to withdraw from the Lord, but to remain in His presence and pray to Him about it. You can acquire this habit if only you resolve from now on always to act in this way.
The second enemy of dwelling within is attachment to something and the captivation of the heart by something through sense-impressions or thoughts about something. This one is worse. You did not have this, and you quickly returned to the old way. If your heart had become attached to something, you would have had to suffer for a long time. Then it would have been necessary first to tear your heart away from that to which it had become attached, and to turn away from it. Keep this in view and guard yourself in every way from both distraction and especially from captivity of the heart. There is one remedy: do not withdraw your attention from the Lord and from the awareness of His presence.
Why do you feel sadness after a long conversation with someone? Because during the conversation you withdrew your attention from the Lord. The Lord finds this displeasing, and He makes you know it through sadness. Accustom yourself to abide inseparably with the Lord in whatever you do, and do all things for Him, striving to conform them to His commandments. And you will never be sad, for you will know that you are doing His work.
(Letter 518. Vol. 3, pp. 208–209)