Heinrich Greeven writes in The Theological Dictionary of the New Testament, Volume VI (edited by Gerhard Kittel and Gerhard Friedrich, Grand Rapids, Michigan: Eerdmans, 1968, pages 763-764):

When the NT [New Testament] uses proskunein [worship (verb: present, active, infinitive)], the object is always something -- truly or supposedly -- divine... It is... not quite correct to say that when those who seek help fall down before the Jewish rabbi this is a secular proskynesis [proskunesis, worship (noun)] before Jesus which is no more than the customary form of respectful greeting. This is certainly not true in Mt. Perhaps there was such a form of greeting... But in Mt. the use of proskunein shows that those who thus fall down already involuntarily and unconsciously declare by their attitude with whom they have to do. The proskynesis of the wise men (Mt. 2:2,11, assumed in 2:8) is truly offered to the Ruler of the world... In comparison with suppliants there is little reference to proskynesis on the part of the disciples. Where this occurs it is especially motivated by dawning recognition of the divine sonship (Mt. 14:33..., cf. Jn. 9:38) or an appearance of the risen Lord (Mt. 28:9, 17; Lk. 24:52).

Paul Achtemier writes in Harper’s Bible Dictionary (San Francisco: Harper and Row, Publishers, Inc., 1985):

Worship, the attitude and acts of reverence to a deity. The term ‘worship’ in the [Old Testament] translates the Hebrew word meaning ‘to bow down, prostrate oneself,’ a posture indicating reverence and homage given to a lord, whether human or divine. The concept of worship is expressed by the term ‘serve.’ In general, the worship given to God was modeled after the service given to human sovereigns; this was especially prominent in pagan religions... As the prophets pointed out, God could not be worshiped only externally. To truly honor God, it was necessary to obey his laws, the moral and ethical ones as well as ritual laws.

Early Christian Worship: In the [New Testament] ‘worship’ still means primarily ‘bow down’ but the word also translates Greek terms signifying service or piety. However, the external form of worship differs radically from that of the OT [Old Testament]. Since the death of Christ constituted the perfect sacrifice, no more sacrifices were needed (Heb. 9:11-12, 24-26). Indeed, the entire institution of Temple, priesthood, sacrifice, and cleansing ritual became obsolete. Rather, the church itself, that is, all the believers, was at once temple and priesthood, inhabited by the Holy Spirit (1 Cor. 6:19; Eph. 2:21-22; 1 Pet. 2:9). As a result, Christian worship was internal rather than external.

Alan Richardson writes in A Theological Word Book of the Bible (edited by Alan Richardson, New York: Macmillan, 1950, pages 287-289):

WORSHIP

Etymology

OT: The general word is 'abodah, from 'abad, to labour, to serve, and usually tranlsated 'the service of God'. To describe the specific act of worship, the word commonly used is hishtahawah, from shaha, to bow, to prostrate oneself.

NT: Corresponding to 'abodah is latreia [noun], meaning originally servitude -- the state of a hired labourer or slave, and thence the service of God -- divine worship. Corresponding to hishtahawah we have proskuneo [verb: present, active, indicative] -- to prostrate oneself, to adore, to worship...

II. WORSHIP IN THE NT

We saw that in the OT a tension developed between the spiritual and ritualistic aspects of worship, the prophets being the exponents of the former, and the Temple priests of the latter. Jesus adopts the prophetic conception of worship, and gives the inward spiritual element absolute primacy. He does not so much attack ceremonial worship as simply ignore it. The true service (worship) of God is adoring and obedient love to him, together with loving service of one's neighbour as God's child. 'This do, and thou shalt live' (Luke 10:25ff.). Implicit in this assertion is the denial that ritual, ceremony or sacrifice have any determinative effect on man's relationship to God. See also Matt. 5:23f., and John 4:20-24, where the same teaching is further enforced. This is not to say that external forms and rules of worship are valueless... Any form or rule is good which is proved by experience to be an aid to that worship which is in spirit and in truth. A further consequence of Jesus' teaching is that the barrier between sacred and secular, worship and daily living, crumbles away. Since worship means the service of God, and this in turn implies loving one's neighbour, it follows that every kindly act performed in this spirit and intention is an act of worship (Matt. 25.34-40; Jas. 1.27).

These principles of Jesus regulate the teaching of the Apostles. Thus as regards the observance of certain days as sacred, St. Paul refuses either to approve or condemn the practice. No absolute rule can be laid down. External observances are to be expressions of inward faith, not matters of outward regulation (Rom. 14:5,6). Let each man act according to conscience in this, subject only to regard to the conscience of his brother.

As with times of worship, so also with places of worship. It was a matter of indifference to the Christians where they met. Christ was with them always and everywhere, and wherever two or three gathered in his name he was in the midst. No building was sacred, because none was secular. Corporate worship was offered in the house of any believer who had a room conveniently large. Expectation of the the Parousia discouraged the building of special places of worship.

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• http://www.bibletexts.com/terms/koine.htm
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