I appeal to you therefore, brethren, and beg of you in view of [all] the mercies of God, to make a decisive dedication of your bodies [presenting all your members and faculties] as a living sacrifice, holy (devoted, consecrated) and well pleasing to God, which is your reasonable (rational, intelligent) service & spiritual worship.
Romans 12:1 (Amplified Bible)
sacrifice is not to be taken lightly. In the Old Testament time, the offering of animals had to be the best, without blemish and probably cost cost much to the owner. And when the animals were being slaughtered, we could hear their cries. Similarly, in hard times as we offer our lives as a living sacrifice (in worship), there are moments of tears, sorrows and pains. But as the Lord consumes our offerings, we will be transformed. Romans 12:1 tells us that this is our reasonable worship.
The story of the woman who broke the abalaster box (John 12:3, Matthew 26:8-9) was met by the disciples' indignant remarks ... "Why this waste?" Waste means giving more than necessary. To Judas and the disciples the waste of money, time and efforts of worship poured upon the Lord could have been channelled for better use. But if the Lord is worthy, then can it be waste? HE IS WORTHY to be WORSHIPPED, WORTHY to be served, WORTHY for me to be in ministry, HE IS WORTHY! Once we see this revelation, what other say about this does not matter anymore.
The Lord said, "Do not trouble her". So let us not be troubled. The Lord's approval upon Mary's action lays the principles of pouring out to Him: that in our service and worship, we need to pour all that we have - our self, upon Him. It is not first of all a question of whether "the poor" (Matthew 26:9) have been helped but a question of whether the Lord has been satisfied.
What does it mean to lay our lives on God's altar? When Abraham obeyed God it means the life of his promised son - Isaac (we know that God provided him a sacrificial lamb for his obedience). But when God did it; it means the life of His own beloved Son - Jesus! Death on the cross but eternal life for all who accept Him. That's what being a living sacrifice is all about. Unlike the old sacrifices, this sacrifice lives! It lives a dedicated life, an altar life. It now belongs to our High Priest. Living sacrifices don't live for them themselves. They live for Another. That's our reasonable (rational, intelligent) service and spiritual worship.
Today, let us lavish upon Him without reservation all our worship.