Verse 3. Let them praise his name in the dance: let them sing praises unto him with the timbrel and harp. Thus let them repeat the triumph of the Red Sea, which was ever the typical glory of Israel. Miriam led the daughters of Israel in the dance when the Lord had triumphed gloriously; was it not most fit that she should? The sacred dance of devout joy is no example, nor even excuse, for frivolous dances, much less for lewd ones. Who could help dancing when Egypt was vanquished, and the tribes were free? Every mode of expressing delight was bound to be employed on so memorable an occasion. Dancing, singing, and playing on instruments were all called into requisition, and most fitly so. There are unusual seasons which call for unusual expressions of joy. When the Lord saves a soul its holy joy overflows, and it cannot find channels enough for its exceeding gratitude: if the man does not leap, or play, or sing, at any rate he praises God, and wishes for a thousand tongues with which to magnify his Saviour. Who would wish it to be otherwise? Young converts are not to be restrained in their joy. Let them sing and dance while they can. How can they mourn now that their Bridegroom is with them? Let us give the utmost liberty to joy. Let us never attempt its suppression, but issue in the terms of this verse a double license for exultation. If any ought to be glad it is the children of Zion; rejoicing is more fit for Israel than for any other people: it is their own folly and fault that they are not oftener brimming with joy in God, for the very thought of him is delight.
—Charles Spurgeon, Treasury of David, http://www.spurgeon.org/treasury/ps149.htm; accessed 9/21/13