The life of the tree is in its roots. The axe has to be laid to the root of the tree. To hate a man in our hearts is secret and nobody can observe that, but if you were to set out to kill that man it would become a public matter and a notorious sin condemned by the world. To be cleansed from secret sins is not only to be forgiven those sins but to cure them, to be rid of them. Keep back thy servant from presumptuous sins.
Presumptuous sins are sins which arise out of pride and lead to presumption.
But after Uzziah became powerful, his pride led to his downfall. Clearly this was a work confined strictly to the priesthood and although he was the King, Uzziah was trespassing on holy ground. The priests did their best to restrain King Uzziah, but it was too late for he was struck with leprosy immediately. Apostasy is a sin of presumption. It is a very deliberate sin which keeps on sinning in spite of knowing the truth.