And it is God who establishes us with you in Christ, and has anointed us, and who has also put his seal on us and given us his Spirit in our hearts as a guarantee (II Corinthians 1:21-22).
Suppose I want to buy a hundred sheep, and go to the nearest sheep-farm, and find what I want. I say to their owner, “I am prepared to give you two

[dollars] each for your sheep.” He contracts to sell me the sheep at the price, I put down the money, and thus the sheep become mine.

What do I do next with them? Drive them home? No, I do not take them home immediately, I am not in such a hurry. Before I drive them home, I take my paint pot, and I put my mark upon every one of my sheep.

If I fail to do this, in driving them home they might get mixed up with some other people’s sheep, and I should not know which were mine.

Alas! that is the way Christians do get mixed up with the people of the world, and often you cannot know the one from the other. It will not do for me to say I think I know that sheep to be mine by a leg mark, or by the turn of his ears, or by his horns: no, I must be sure of my own, and so I put my peculiar mark on each. Similarly, in giving the Holy Ghost, God puts His mark, clearly and distinctly, upon all His own.

But let me ask you this: Did the mark I put upon the sheep make it mine? You know it did not. I put the mark on it because it was mine, but it was the money I paid for it that made it mine.

So it is the work of Christ, the blood of Christ, that redeems, and saves, and brings the soul to God, and then the Holy Ghost is given to dwell in the believer as God’s seal upon him, and the earnest of the good things that belong to him, so that the believer is sure of glory; his heart is now put in possession of eternal things, and he enjoys them…

A Christian has thus actually begun his heaven down here on earth. People often say, “We shall be happy in eternity.” Why not be happy now? Why put it off? The Lord wants you to be happy down
here.

Oh, but, you say, I have seen a great many people who say they are Christians, and they are not happy. More’s the pity, they ought to be happy, if they are Christians. But perhaps these may not have been real Christians, still that does not prove there are no real ones.

Young men and women think they have found a reason for remaining unbelievers, because they have found some “Christians” who are not genuine. I ask then, When you get hold of a one hundred dollar bill, do you always put it in the fire, because now and then a bad hundred dollar bill has turned up? No — you know better, for what does a bad banknote prove? It confirms that there are plenty of good ones. So if I meet with a counterfeit saint, he only proves that there are real ones.

Now what is a Christian? He is a man clear of death and judgment, brought to God, his sins forgiven: one who has a new nature, who has received the Holy Ghost, and who has a new place before God in Christ, of whose body he is a member; one who knows he is a child of God, an heir of God, and a joint-heir with Christ; who has nothing but glory now before him, and is looking for the coming of our Lord Jesus Christ, to take him home to the rest and glory of the Father’s house. It is therefore a wonderful thing to be a Christian: an unspeakably blessed thing! — W.T.P. Wolston (1840-1917).

(Quoted in the 496-page book, His Victorious Indwelling)