And the sun was darkened, and the veil of the temple was rent in the midst.
a) Jesus, when dying, addressed God as His Father, and thus, with His last words, testified to His Divinity.
b) Innanimate nature bore witness that the most terrible of crimes, even the murdar of God, had taken place on Calvary. The sun hid itself so as not to witness the death agony of the "Sun of justice;" the earth heaved and the rocks rent themselves asunder, for He who laid the foundations of the earth and built the mountains was dying! Even the kingdom of the dead (by opening of the graves) testified that the Lord of life had conquered death by His Death.
[From 'A Practical Commentary on Holy Scripture' by Bishop Knecht, D.D.]
(1899 Douay-Rheims Bible)