“Behold, God is my salvation; I will trust, and will not be afraid; for the LORD GOD is my strength and my song, and he has become my salvation.” —Isaiah 12:2

“Behold” is a word of wonder; it is intended to excite admiration. Wherever you see it hung out in Scripture, it is like an ancient sign-board, signifying that there are rich wares within, or like the hands which solid readers have observed in the margin of the older Puritanical books, drawing attention to something particularly worthy of observation.

Charles Spurgeon

Behold is notable that when behold (hinneh) is used in Isaiah, it always introduces something relating to future circumstances

W E Vine

Note that they will not say that God provided salvation but that He is salvation. Salvation is a Person, not a program, or a system, or a ritual, or a liturgy. Salvation is a Person, and that Person is the Lord Jehovah, the Lord Jesus Christ.

J Vernon McGee