Charles H. Spurgeon on Psalms 105:8

He hath remembered his covenant for ever. Here is the basis of all his dealings with his people: he had entered into covenant with them in their father Abraham, and to this covenant he remained faithful. The exhortation to remember (Ps 105:5) receives great force from the fact that God has remembered. If the Lord has his promise in memory surely we ought not to forget the wonderful manner in which he keeps it. To us it should be matter for deepest joy that never in any instance has the Lord been unmindful of his covenant engagements, nor will he be so world without end. O that we were as mindful of them as he is. The word which he commanded to a thousand generations. This is only an amplification of the former statement, and serves to set before us the immutable fidelity of the Lord during the changing generations of men. His judgments are threatened upon the third and fourth generations of them that hate him, but his love runs on for ever, even to "a thousand generations." His promise is here said to be commanded, or vested with all the authority of a law. It is a proclamation from a sovereign, the firman of an Emperor whose laws shall stand fast in every jot and tittle though heaven and earth shall pass away. Therefore let us give thanks unto the Lord and talk of all his wondrous works, so wonderful for their faithfulness and truth.