Though I walk in the midst of trouble - Though I am in the low vale of sorrow, I shall not be overlooked or forgotten. This implies that the writer was then in trouble, and it expresses the conviction that whenever he should be in trouble God would remember him, and give him life and strength.
Thou wilt revive me - Thou wilt cause me to live; thou wilt give me life. Psalms 30:3. Compare the notes at Psalms 71:20. The meaning is, Thou wilt give me life - vigor - strength - to bear the trouble.
Thou shalt stretch forth thine hand - As one does when he is about to inflict a blow.
Against the wrath of mine enemies ... - In reference to all their attempts to destroy me. Thou wilt meet their wrath by thy power, and I shall be safe.