As one moves through the Sign, one recites, at the forehead, "Lord "; at the stomach, "Jesus Christ", on the right shoulder, "Son of God"; and on the left shoulder, "have mercy on us" followed by a bow(to the ground during great lent).
Joining two fingers together-the index and the middle finger-and extending them, with the middle finger slightly bent, represents the two natures of Christ: His Divinity and His Humanity. He is God according to His divinity and Man according to His hummanity, perfect in both natures. The index finger represents His divinity, while the middle finger repersents His hummanity, since He came down from on high and saved those below. The bending of the middle finger is interperted to mean that He bowed the heavens and came down upon the earth for our salvation.
And thus it proper to make the Sign of the Cross and to bless; thus was it laid down and ordained by the holy fathers; such is the power of the Sign of the Cross, with which we faithful sign ourselves when we pray, confessing sacramentally the Saviour's economy: His being begotten of God the Father before all creation; His decent to earth from on high; His Crucifixion; and His second coming, which is the sealing of His entire philanthropic dipensation concerning us.
The sign of the cross must be made according to the rules, in the form of a cross; and the right hand, that is, the dextral hand, must be used in crossing oneself, with the thumb and the two lower fingers joined together, and the extended index finger joined to the middle finger, slightly bent; thus should prelates [and] priests give their blessing and thus should men cross themselves. . . . It befits all Orthodox Christians to hold their hand thus, and to make the sign of the cross upon their face with two fingers, and to bow, as we said before. If anyone should fail to give his blessing with two fingers, as Christ did, or should fail to make the sign of the cross with two fingers, may he be accursed.. . ., Chapter 31 of The Council Of The Hundred Chapters.