Let’s begin with the Cross. Here is where we learn the lesson of sacrifice and offering.
Jesus came among us. Jesus is God joining Himself to humanity. He became one of us to inseparably join His Divinity with our humanity, to live our life and to suffer our sufferings. He did so in order that we, in our humanity, may also be one with His Divinity.
He did so also to take away our sin and death and separation from God — the consequences of our rebellion against God, so that we may go free without paying for the just cost of our transgression.
The Father had a plan. We don’t quite understand this plan. But the plan is: Jesus is to take on all our sufferings onto the Cross, and He will offer all these meaningless sufferings as a freely offered sacrifice to the Father, and the Father in exchange will grant salvation and forgiveness to the whole world, to everyone, to each of us.
Jesus’ dying on the Cross, therefore, reveals the secret of God’s mercy. We all suffer, and suffering is not from God and so is meaningless in itself. But for the suffering that we cannot avoid, He shows us that we can make it into a sacrifice, a useful offering to God; and mysteriously, God can use it to save souls. God the Father simply delights in exchanging our sacrifices with salvation, that is why it is called redemption: we redeem used bottles or recyclable material for cash, but in this case we get eternal life.
Jesus invites us: if you want to be my disciple, you must deny yourselves, take up the cross, and follow after me.
He is inviting us: there are sufferings in life that are inescapable and inevitable.
He is saying, follow my example: accept these sufferings by turning them into a free offering to God the Father, and ask Him to use it to help those most in need, those who are heading toward hell and destruction.
A common practice in the Catholic tradition is: offer each hour to God at the hour. At 8am as you begin work, tell God I’m offering this hour to praise You, and I offer every temptation that provokes me to anger and pride, that You may use it to help converting sinners. At 9am, offer to God the inconvenience I suffer or the misunderstanding from others that I have to endure. And so on. If we strive to practise this every day, difficult virtues would become easy to achieve, and harden vices would be unrooted, because we have now added new meanings to our effort — to desire what Jesus desires on the Cross, to save souls.