Psalm 66:8 O bless our God, ye people, and make the voice of his praise to be heard.
Come and see the works of God: he is terrible in his doing toward the children of men (v. 5). The response to seeing and believing the great works of God in Creation and Salvation is to bless God (say good things about Him), and call on all to make the voice of His praise to be heard. Believing is seeing, and seeing the terrible love of God on the cross and the awesome power of God at the tomb calls forth blessing and praise as the natural response to the great power of God to save.
The Lord is terribly bad toward sin and evil, but terribly good toward the sinner. The Holy Spirit blesses us with faith through the Gospel to see. We believe. We see. We praise. Our New Life is full of blessing and praise.