Question:
When people praised the Lord in Old Testament times, what practices were done then that are not acceptable in today’s assembly? Would clapping be considered Old Testament worship?

Answer:
Let me begin this answer by quoting the words of Jesus to the woman at the well, “Woman, believe Me, the hour cometh, when ye shall neither in this mountain, nor yet at Jerusalem, worship the Father. Ye worship ye know not what: we know what we worship: for salvation is of the Jews. But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship Him. God is a Spirit: and they that worship Him must worship Him in spirit and in truth” (John 4:21-24).

These words of our Lord Jesus on the subject of worship reveal three great changes that were to occur in worshipping God: (1) The PLACE of worship; (2) The PERSON to be worshipped; and (3) The PRAISE in worship. Let us look briefly at each one.
(1) God’s earthly people, the Jews, worshipped God in JERUSALEM (vs. 21). This was the Divine Center for worship where God had chosen to place His Name (see Deuteronomy 12:10-14; 1 Kings 8:1, 13, 27-29). But today God’s heavenly people, the church, can by faith “enter into the holiest [heaven] by the blood of Jesus” (Hebrews 10:19). We can do this ANYWHERE on earth. Matthew 18:20 says, “Where two or three are gathered together [unto] My Name, there am I in the midst of them.”
(2) In Old Testament times, the Jews worshipped God as JEHOVAH. Today He has been revealed to every child of God as the FATHER (John 4:21, 23) and we are privileged to worship Him with the assurance that we are “children of God by faith in Christ Jesus” (Galatians 3:26). Believers in the Old Testament were children of God, but they did not have the knowledge of this relationship with God as Father.
(3) Israel’s worship [praise] of God was fleshly; the church worships “in spirit and in truth.” By FLESHLY we mean that it was a form of worship which appealed to man’s five physical senses. They had musical instruments to appeal to the sense of HEARING, incense for the sense of SMELL, animal sacrifices for the sense of TOUCH and TASTE, and a beautiful temple and priestly garments for the sense of SIGHT. In contrast, the church worships by faith, with nothing ritualistic or sensuous to distract the heart from being taken up with worshipping the Father (and the Son). To worship “in spirit” implies this.To touch on your question about “clapping,” I suggest you read Psalm 47. It starts out, “O clap your hands, all ye people; shout unto God with the voice of triumph.” The whole Psalm describes the time when Israel shall be redeemed (after the rapture of the church) and will be the nucleus of Christ’s Millennial kingdom. Their praise, and that of the saved Gentiles, will take on much of the same character as in Old Testament times (which will appeal to the five senses).