Charles Ellicott Commentary Psalms 21:4

"He asked life of thee, thou gavest it him, Even length of days for ever and ever." — Psalms 21:4 (ASV)

For ever and ever. — This is merely a term for indefinite length. (Compare the common salutation of a king: 1 Kings 1:31; Nehemiah 2:3; Daniel 3:9.) An allusion to the eternal kingdom of the Messiah is not to be forced on the passage.