Jamieson, Fausset and Brown on Psalms 118:22-23

22-23. These words are applied by Christ (Mt 21:42) to Himself, as the foundation of the Church (compare Ac 4:11; Ep 2:20; 1Pe 2:4, 7). It may here denote God's wondrous exaltation to power and influence of him whom the rulers of the nation despised. Whether (see on Psa 118:1) David or Zerubbabel (compare Hag 2:2; Zec 4:7-10) be primarily meant, there is here typically represented God's more wonderful doings in exalting Christ, crucified as an impostor, to be the Prince and Saviour and Head of His Church.