What does Psalms Chapter 91 say, and which statements belong to its speaker?

Bonum est confiteri is the incipit and the heading calls for praise of wondrous works. The inscription is a psalm of a canticle on the sabbath day, not a witnessed musician's performance. It is good to praise the Lord and sing the Most High's name, show mercy in morning and truth at night, upon a ten-stringed instrument, psaltery and harp. God has given delight in His doings and the speaker shall rejoice in His hands' works.

He exclaims that works are great and thoughts exceedingly deep; the senseless shall not know and the fool will not understand. Wicked people shall spring like grass and workers of iniquity appear that they may perish forever, while God is Most High forever. Enemies shall perish and all iniquity workers be scattered. This future declaration is not a newly observed historical downfall.

The speaker's horn shall be exalted like a unicorn's, and old age in plentiful mercy. His eye has looked down upon enemies and ear shall hear malignant opponents' downfall. The just shall flourish like palm and grow like Libanus cedar; planted in God's house, they shall flourish in His courts, increase in fruitful old age and be well treated, that they may show God's righteousness and absence of iniquity. The comparisons do not supply a physical-vitality guarantee or a new Sabbath ritual rule.