Charles H. Spurgeon on Psalms 89:36

His seed shall endure for ever. They shall continue for ever in three senses. First. In the succession of their race to the end of the world. It will never be cut off. —"The Church is in danger!" What Church? "Upon this rock", says he, "I will build my Church; and the gates of hell shall not prevail against it." Yea, his people shall continue to increase in number and excellency. We shall leave the world better than we entered it: and so will our children; till Jerusalem shall be established, and be made a praise in the whole earth. Secondly. In their religious character to the end of their own life. If left to themselves, we could not be sure of their persevering to the end of a day or an hour. But they are kept by the power of God, through faith, unto salvation. He upholdeth them with his hand. They shall hold on their way. In all their dangers they shall be more than conquerors. Thirdly. In their glorified state, through eternal ages. The world passeth away, and the lusts thereof; but he that doeth the will of God abideth for ever. All other greatness is only for life: it is frequently less durable —at death it ends. But then, the Christian's greatness —I will not say, begins; for it began the moment he prayed —but then it continues, increases, and is perfected. —William Jay.