Jesus knows that his disciples will be tested and he assures them that the Holy Spirit will give them what they need in their time of adversity. He warns them, however, that it's possible to reject the grace of God and to fall into apostasy (giving up the faith) out of cowardice or disbelief. The scriptural expression to deny someone means to disown them. Jesus also speaks against blaspheming the Holy Spirit. What is blasphemy and why is it reprehensible? Blasphemy consists in uttering against God, inwardly or outwardly, words of hatred, reproach, or defiance. It's contrary to the respect due God and his holy name. Jesus speaks of blaspheming against the Holy Spirit as the unforgivable sin. Jesus spoke about this sin immediately after the scribes and Pharisees had attributed his miracles to the work of the devil instead of to God.