…joy and gladness shall be found therein, thanksgiving, and the voice of melody…Therefore the redeemed of the LORD shall return, and come with singing unto Zion; and everlasting joy shall be upon their head: they shall obtain gladness and joy; and sorrow and mourning shall flee away. -Isaiah 51:3, 11

“Joy and gladness shall be found therein; thanksgiving and the voice of melody.” You notice the doubles. The parallelism of Hebrew poetry, perhaps, necessitated them. Still, I am prone to remember how John Bunyan says that “all the flowers in God’s garden bloom double.” We are told of “manifold mercies,” that is, mercies which are folded up one in another, so that you may unwrap them and find a fresh mercy enclosed in every fold. Here we have “joy and gladness, thanksgiving and the voice of melody.” Just so; the Psalmist tells us of our soul being satisfied with “marrow and fatness”-two things. Elsewhere he speaks of “loving-kindness and tender mercy”-two things again. The Lord multiplies His grace. He is always slow to anger, but He is always lavish of His grace. See here, then, God will give His people an overflowing joy, an inexpressible joy, a sort of double joy, as though He would give them more joy than they could hold; joy and then gladness; thanksgiving and the voice of melody.

Oh! what a delightful thing must a visitation from God be to His Church! Without God, all she can do is to groan…Let God visit His Church, and there is sure to be thanksgiving and the voice of melody. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/3514.cfm