Repentance is simply renouncing sin, turning round from darkness to light, from the power of Satan unto God. He is like the prodigal who, when he sat in the swine yard amongst the husks and the filth, fully resolved, and at last acted. He went, and that was the test of his repentance. He might have sat resolving and promising till now, if he had lived as long, and he would never have got the father's kiss, the father's welcome, if he had not started. That is Jesus Christ's own beautiful illustration of true repentance.
Sub mission is the test of true repentance.
My child may be willing to do a hundred and fifty other things, but if he is not willing to submit on the one point of controversy he is a rebel and remains one until he yields. Here is the difference between a spurious and a real repentance. Abraham might have been willing to give up every other thing he possessed, but if he had not been willing to give up Isaac, all else would have been useless. It is your Isaac that God wants. You have an Isaac, just as the young ruler had his possessions.