Some Whys
Why do we clap our hands?
The act of clapping our hands is a form of praise which is mentioned frequently in the scriptures:
"O clap your hands, all ye people; shout unto God wuth the voice of triumph." (Psalm 47:1) KJV
"For Ye shall go out with joy, and be led forth with peace: the mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands." (Isaiah 55:12) KJV
Why do we lift our hands?
The act of lifting our hans is a form of praising the Lord. Some scriptures that mention praise are:
"Thus will I bless thee while I live. I will lift up my hands in thy name." (Psalm 63:4) KJV
"I will therefore that men pray everywhere, lifting up holy hands, without wrath and doubting." (1 Timothy 2:8)
Why do we sing as we do?
"And be not drunk with wine, wherein is exess; but be filled with the Spirit; speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord." (Ephesians 5:18 & 19) KJV
"Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your heart to the Lord." (Colossians 3:16) KJV