For when God made promise to Abraham, because He could swear by no greater, He sware by himself, saying, Surely blessing I will bless thee, and multiplying I will multiply thee. – Hebrews 6:13, 14

The blessing of the church is the increase of the church. The two go together: “Blessing, I will bless thee, and in multiplying, I will multiply thee.” How much are Christians to be multiplied in the world? At the present moment we do not seem to be increasing as fast as the population. I am afraid that the number of converted persons relatively to the population is scarcely as great as it was thirty years ago; we long to be multiplied at a very different rate from this-and we shall be if we have faith in our God. Hear ye the covenant word: “Look now toward heaven, and tell the stars, if thou be able to number them: and He said unto him, So shall thy seed be. And in thy seed shall all the nations of the earth be blessed.” These are lines from the covenant, which is sure to all the seed and can never be broken. We have been called and blessed, and it is of necessity that we increase also. We are bound to increase; we are destined to overrun the nations; the Hittites, the Hivites, the Amorites, of Popery, Mahometanism, and Idolatry are in the land, but their false systems are utterly to perish. Jesus at the head of His people shall drive them out-I mean not the men, but their evil beliefs. They may take notice to quit, for He is coming before whom all men must bow. O that ere He Himself shall appear His spiritual presence in the midst of His church might suffice for victory, that all mankind might call Him blessed. We are bound to increase, till the wilderness and the solitary place shall be glad for us, and the desert shall rejoice and blossom as the rose. Upon the church in her vigour shall yet descend the blessings of the tribes of Joseph. “His glory is like the firstling of his bullock, and his horns are like the horns of unicorns: with them he shall push the people together to the ends of the earth.” The success of truth is the battle of the Lord, and the increase of His church is according to His own promise, therefore in quietness we may possess our souls. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1596.cfm