In the OT it was mostly a joyful spiritual exercise of triumphant worship involving actions and words directed towards God (Ex 15:20,21; 2 Sam 6:16; Ps 30:1, 149:3, 150:4). Dancing can also be a mode of expression for idolatrous worship and seductive entertainment (Ex 32:19; Mk 6:17-28).

When God was worshiped, the men and women did not mingle, as is the case with eastern religions and modern secular dance.  Dancing which involves close contact with the opposite sex tends to arouse strong emotional and sensual feelings which are contrary to the teachings of Scripture to purify oneself from all impure thoughts and

What is the reason and motive for this activity?

abstain from lusts of the flesh and all kinds of evil (1 Thes 4:7, 5:22; 1 Pet 2:11). Even though we are born-again, we still have the old carnal nature within which constantly needs to be denied. The Bible counsels "Flee [runaway from] the evil desires of youth" (2 Tim 2:22). Any dancing that brings attention to yourself or your body with movements unbecoming a Christian and so stirring up sinful desires in ourselves or others is sinful and brings shame on God. Everything should be done decently and in order for the glory of God (1 Cor 10:31, 14:40). Any worshipful dance should be God-focused, praiseworthy and honouring to Him, not drawing attention to the dancers or a cause of temptation for all our activity should be governed by the awareness that we are not to cause another to stumble (Mt 18:6).

We are to do things that are honourable and respectful in the sight of all men, glorifying God in our bodies and exalting Christ (Rom 12:17; 1 Cor 6:19,20; Phil 1:20,  4:8). This means we shouldn't engage in questionable, lustful or sensual behaviour (Rom 6:12, 14:23; 2 Cor 12:20,21; 1 Thes 5:21,22; 1 Jn 2:16).

See also: desires, lust, night club, purity, temptation, thinking/thoughts.