And lastly, as every one knows, what else is the sign of Christ but the cross of Christ? For unless that sign be applied, whether it be to the foreheads of believers, or to the very water out of which they are regenerated, or to the oil with which they receive the anointing chrism, or to the sacrifice that nourishes them, none of them is properly administered.
-St. Augustine (A.D. 354-430)
An article from Christianity Today on the subject:
Never leave home without making the sign of the cross.... You should not just trace the cross with your finger, but you should do it in faith.
-John Chyrsostom (A.D. 347-407)
This [the letter Tau] bears a resemblance to the figure of the cross; and this prophecy [Ezek. ix. 4] is said to regard the sign made by Christians on the forehead, which all believers make whatsoever work they begin upon, and especially at the beginning of prayers, or of holy readings
-Origen (A.D. 185- 284)
In all our travels and movements, in all our coming in and going out, in putting on our shoes, at the bath, at the table, in lighting our candles, in lying down, in sitting down, whatever employment occupies us, we mark our foreheads with the sign of the cross.
-Tertullian (A.D. 160- 225)
Let us not, therefore, be ashamed of the cross of Christ, but even though another hide it do thou openly seal it on thy brow, that the devils beholding that royal sign may flee far away trembling. But make thou this sign when thou eatest and drinkest, sittest or liest down, risest up, speakest, walkest; in a word, on every occasion, for He who was here crucified is above in the heavens.
-St. Cyril of Jerusalem (c. A.D. 315-86)
Many have been crucified throughout the world but none of these do the devils dread, but Christ having been crucified for us, when they see but the sign of the cross the devils shudder.
-St. Cyril of Jerusalem
After the sign of the cross, grace immediately thus operates, and composes all the members and the heart, so that the soul from its abounding gladness seems as a youth that knows not evil.
-St. Macarius of Egypt (A.D. 300- 390)
Servant of God, Remember
William J. Blew (1852)
Servant of God, remember
The stream thy soul bedewing,
The grace that came upon thee
Anointing and renewing.
When kindly slumber calls thee,
Upon thy bed reclining,
Trace thou the cross of Jesus,
Thy heart and forehead signing.
The cross dissolves the darkness,
And drives away temptation;
It calms the wavering spirit
By quiet consecration.
Begone, begone, the terrors
Of vague and formless dreaming;
Begone, thou fell deceiver,
With all thy boasted scheming.
Begone, thou crooked serpent,
Who, twisting and pursuing,
By fraud and lie preparest
The simple soul’s undoing.
Tremble, for Christ is near us,
Depart, for here He dwelleth,
And this, the sign thou knowest,
Thy strong battalions quelleth.
Then while the weary body
Its rest in sleep is nearing,
The heart will muse in silence
On Christ and His appearing.
To God, eternal Father,
To Christ, our King, be glory,
And to the Holy Spirit,
In never ending story.