Psalms 126:3

The Lord hath done great things for us - All that the people around us say is true. We see it; we feel it; we acknowledge it. Those to whom this pertained would see it more clearly than those who had merely observed it. A surrounding world may see in the conversion of a man, in his being turned from sin, in the influence of religion upon him, in his comfort, calmness, and peace, that "the Lord has done great things" for him; but he himself, while he responds most fully to what they say, will see this more clearly than they do. There is more in his redemption, his conversion, his peace and joy, than they do or can perceive, and with emphasis he himself will say, "The Lord has done great things for me."

Whereof we are glad - It fills our souls with joy. If this is understood of the returning Hebrews - coming back from the captivity in Babylon - all must see how appropriate is the language; if it be applied to a sinner returning to God, it is no less suitable, for there is nothing that so fills the mind with joy as a true conversion to God.