Context: The poet, encompassed by trouble, praises God for His eternal mercy and strength. Though he is surrounded by his enemy, the psalmist is confident of victory through God. Continuing his praise of the Lord Who exalts the downtrodden, and anticipating the holy day, the psalmist says:
The stone which the builders refused is become the head stone of the corner.
This is the Lord's doing; it is marvelous in our eyes.
This is the day which the Lord hath made; we will rejoice and be glad in it.