Christians often talk about holiness and obedience to God, and following Jesus as our Lord and Master has been vitally important to Christians for 2,000 years. But did you know that it's the humanity of Jesus that makes us holy? Hebrews 10:9-10 states, "Then he said, 'Here I am, I have come to do your will.' He sets aside the first to establish the second. And by that will, we have been made holy through the sacrifice of the body of Jesus Christ once for all" (NIV). This passage is part of a larger argument in Hebrews 10 that Jesus' birth and incarnation were already prophesied.
In Hebrews 10:5-7, Psalm 40:6-8 is quoted in order to make the case that the pre-incarnate Jesus knew he was coming to earth and discussed this reality with the Father. That is why Hebrews 10:9 claims "he [Jesus] set aside the first to establish the second." What came first was sacrifice and offering for our sins, and what comes second to replace it is Jesus' offering of his own body for those sins. But the point Hebrews 10:9-10 is making is that the humanity of Jesus is the means to accomplish all of this. Jesus is the one who says, "Here I am, I have come to do your will," and it's God's will that Jesus desires to accomplish. Further, the context makes clear that God's will is for Jesus to take on flesh and, being fully God, also be fully human. Jesus fulfills and carries out God's will by becoming a human, and Jesus provides us with two benefits by means of his human will and human body.
First, Jesus sets aside our need to continually make animal sacrifices and offerings to atone for our sins by himself making complete atonement by his incarnation and death. It's not that sacrifices and offerings are unnecessary to atone for our sins. Instead, it's that only Jesus can make the necessary sacrifice and offering to atone for us - which he has!
Second, we are made holy by the sacrifice of Jesus' body once for all. Not only does Jesus no longer die to make us holy, since his death has already made the necessary holiness accessible to us, but Jesus' own body offered on our behalf is what makes us holy. Christians often think holiness either comes from their own effort or God's transforming grace, but the truth is more jolting and/or joyous than that: holiness is provided to us by the work of Jesus the God-man, by means of his body being tortured, killed, made dead, and buried for us (which itself is grace).
Friends, it is true that you can't make yourself holy, but it is even more true that Jesus makes you holy by his own humanity - which is a marvelous treasure!