Orthodox Christians have received from the Holy Fathers and observe the following practices throughout the world:
1. Entering the church one makes the sign of the Cross three times, accompanying each with a little bow* and says:
"Thou hast created me, O Lord, have mercy."
"O God, be merciful to me, a sinner."
"Countless times have I sinned, O Lord, forgive me." 2. Then, having bowed to those on the right and the left, one stands in one's place and listens to the psalms and prayers read in church. One does not say prayers of one's own choosing or read any from prayerbooks, lest one be judged by the holy Apostle Paul for having forsaken the assembly of the Church (Heb. 10:25). 3. Great and little bows should not be made according to one's pleasure but according to the regulations of the holy apostles and fathers, namely: at the Trisagion ("Holy God..."), "O come let us worship," and the threefold "Alleluia," one makes the sign of the Cross three times and three little bows. This is also done during the reading of "Vouchsafe, O Lord," and again at the beginning of the Great Doxology (Glory be to God on high...") and after the priest says, "Glory to Thee, Christ God, our hope." At every exclamation of the priest and also when the reader chants, "More honorable than the Cherubim..." one ought to make the sign of the Cross and a lesser reverence. On ordinary days great bows are made during the Liturgy:
a) at the beginning of "It is meet and right..."
b) at the end of "We sing unto Thee..."
c) at the end of the hymn to the Holy Virgin, "It is meet and right to bless thee..." or its substitute;
d) at the beginning of the Lord's prayer;
e) when the Holy Gifts are brought forth for Communion;
f) at the words "Always, now and ever..."
At Matins of Vigil a great bow is made at "The Theotokos and Mother of the Light let us magnify..."
4. On Sundays, from Holy Pascha until Trinity Day, from the Nativity of Christ until Theophany, and on feasts of the Transfiguration and the Elevation of the Holy Cross (on which last only three great bows are made to the Cross), the Holy Apostles utterly forbid kneeling and great bows, concerning which St. Basil the Great wrote to the Blessed Amphylochius. The First and Sixth Ecumenical Councils have also thus ruled, for Sundays and other feasts of the Lord serve as a reminder of our adoption by God, according to the Apostle: "Wherefore thou art no more a servant, but a son" (Gal. 4:7): for the reverences propoer to servants are not becoming to sons.
5. Orthodox Christians do not kneel at their own pleasure, but rather at the words of the priest (or deacon), "Again and again on bended kneels..." do they kneel; the customs of kneeling at will and of striking one's breast with the hand come from the Western heretics and are not permitted in the Orthodox Church. Orthodox Christians, in accordance with Church rule, make great bows at the appointed times, bowing to the ground and standing upright immediately.
6. In church, whenever the faithful are blessed with the Cross or Gospel Book, with an icon or the chalice, they make the sign of the Cross and bow the head. When they are blessed with candles, the hand, or are censed, Orthodox Christians ought not to make the sign of the Cross but only bow the head. However, during the week of Holy Pascha when the priest censes with the Cross, all make the sign of the Cross and answer, "Truly, He is risen!" In this way then ought we to distinguish between the reverences due holy things and those which are due to persons, even if they be of priestly rank.
7. When receiving a blessing from either a priest or a bishop, a Christian kisses the right hand of him who bestows the blessing and does not make the sign of the Cross. It is not proper to kiss the left hand of clergy, for this is a Jewish usage, but the right hand from which we have received the blessing.
8. According to the teaching of the Holy Fathers, the sign of the Cross is to be made in the following manner: the thumb and first two fingers of the right hand are joined at their tips and the other fingers folded across the palm. We then touch the forehead, breast, right and left shoulders and make a slight bow. Of those who sign themselves with all five fingers, or who bow before finishing the Cross, or simply wave their hand in the air or before their breast, St. John Chrysostom says: "The devils rejoice at these mad gestures." On the other hand, the sign of the Cross, properly made with faith and reverence, terrifies the devils, lessens the sufferings caused by sins and calls down divine grace.
RULES FOR BOWS AND THE SIGN OF THE CROSS
SIGN OF THE CROSS WITHOUT BOWS: 1. At the middle of the Hexapsalm, at the triple Alleluia, three times.
2. At the beginning of the Creed.
3. At the dismissal -- "Christ our true God..."
4. At the beginning of a reading from Holy Scripture: Gospel, Apostle or Old Testament Lesson.
SIGN OF THE CROSS WITH THE LITTLE BOW:
1. When entering or leaving a church -- three times. 2. At every petition of the litanies.
3. At the exclamation of the priest giving glory to the Holy Trinity.
4. At the words, "Take, eat..." "Drink ye all of this..." "Thine own of Thine own..." and "Holy Things for the holy!"
5. At the words, "Higher in honor than the Cherubim..."
6. At the words, "Let us worship...", "We worship...", "We adore...", and "We fall down before..."
7. During "Alleluia," "Holy God," "O come, let us worship," and "Glory to Thee, Christ God," before the dismissal the sign of the Cross with the little bow is made three times.
8. During the first and ninth odes of the canon, at the first refrain to the Lord, the Mother of God or the Saint.
9. After each stikhira -- at which time the choir which has finished singing makes the sign of the Cross.
10. During the Litiya, at each of the first three petitions we sign ourselves and bow three times; after the remaining two petitions we sign ourselves and bow once.
SIGN OF THE CROSS WITH THE GREAT BOW (PROSTRATION):
1. During fasts, when entering and leaving church -- three times. 2. During fasts, at each "...we magnify thee" in the refrain to the Canticle of the Mother of God (Magnificat).
3. At the beginning of "It is meet and right to worship the Father..."
4. After the "We sing unto Thee..."
5. After the hymn to the Mother of God or its substitute.
6. At the exclamation, "And grant us, O Master...", introducing the Lord's Prayer.
7. When the Holy Gifts are brought forth for Communion and again after Communion.
8. During the Great Fast at Great Compline during the singing of "Most holy Mother of God..." and at each of its several accompanying petitions; at Vespers, at the end of "Virgin Mother of God rejoice," and the two hymns following.
9. During fasts at the end of each section of the prayer "O Lord and Master of my life..."
10. During fasts, at the three concluding petitions -- "Remember me, O Lord, when..."
LITTLE BOW WITHOUT THE SIGN OF THE CROSS:
At the words: 1. "Peace be to all."
2. "The blessing of the Lord be upon you..."
3. "The grace of our Lord Jesus Christ..."
4. "And may the mercies of our great God..."
5. When the deacon exclaims, "And unto the ages of ages" (after "For Thou art holy, O our God...").
THE SIGN OF THE CROSS IS NOT TO BE MADE:
1. During psalms. 2. Generally, while singing.
During litanies by the choir which will make the responses.
Making the sing of the Cross and bows are allowed after singing, not during the concluding words of a given piece.
Prostrations are not allowed on Sundays; from Nativity through Theophany; from Pascha until Pentecost Sunday; on the feast of the Transfiguration; and on the feast of the Elevation of the Cross (except the three prostrations of the Cross).
Prostrations cease with the entrance during Vespers of the feast and are not resumed until after "Vouchsafe, O Lord..." during Vespers on the day of the feast itself.
* In this article the terms poyasny/zemnoy poklon have been translated as little/great bow. The little bow is made by bending from the waist until the fingers of the extended right hand touch the ground; the great bow, by kneeling and touching the forehead to the ground (Trans. note).
Source: Orthodox Life, Volume 26, Number 1 (Jan.-Feb. 1976), pages 24-27.