Seventh-Day Adventists/Christ's Heavenly Ministry
Please explain in detail the correct version of Christ's current ministry as mediator in the heavenly sanctuary to show that what He's doing up there is different from SDA's Fundamental Belief No. 24. Thanks.
Thank you so much for your question. I must say that it really was an eye opener to discover what Christ is currently doing, unlike what I was taught and what I was fearful of as an SDA.
Following is their Fundamental Belief #24:
Christ’s Ministry in the Heavenly Sanctuary Z24
There is a sanctuary in heaven, the true tabernacle which the Lord set up and not man. In it Christ ministers on our behalf, making available to believers the benefits of His atoning sacrifice offered once for all on the cross. He was inaugurated as our great High Priest and began His intercessory ministry at the time of His ascension
. In 1844, at the end of the prophetic period of 2300 days, He entered the second and last phase of His atoning ministry. It is a work of investigative judgment which is part of the ultimate disposition of all sin, typified by the cleansing of the ancient Hebrew sanctuary on the Day of Atonement. In that typical service the sanctuary was cleansed with the blood of animal sacrifices, but the heavenly things are purified with the perfect sacrifice of the blood of Jesus. The investigative judgment reveals to heavenly intelligences who among the dead are asleep in Christ and therefore, in Him, are deemed worthy to have part in the first resurrection. It also makes manifest who among the living are abiding in Christ, keeping the commandments of God and the faith of Jesus, and in Him, therefore, are ready for translation into His everlasting kingdom. This judgment vindicates the justice of God in saving those who believe in Jesus. It declares that those who have remained loyal to God shall receive the kingdom. The completion of this ministry of Christ will mark the close of human probation before the Second Advent. (Heb. 8:1-5; 4:14-16; 9:11-28; 10:19-22; 1:3; 2:16, 17; Dan. 7:9-27; 8:13, 14; 9:24-27; Num. 14:34; Eze. 4:6; Lev. 16; Rev. 14:6, 7; 20:12; 14:12; 22:12.)
I underscored the part that I believe is currently happening and that can be supported from Scripture.
Following is a list (in random order) of what the Bible tells us Jesus is currently doing in the heavenly sanctuary. Perhaps you can add to it.
He is our Intercessor:
(He makes requests on our behalf and brings our prayers before the Father. Jesus' sacrifice made Satan's accusations null and void because we are covered by the blood of the Lamb. when we accepted Him into our lives)
Hebrews 7:25 NIV
Therefore he is able to save completely those who come to God through him, because he always lives to intercede for them.
Romans 8:34 NIV
Who then is the one who condemns? No one. Christ Jesus who died---more than that, who was raised to life---is at the right hand of God and is also interceding for us.
He is our Defender against the accusations of Satan:
Revelation 12:10 NIV
Then I heard a loud voice in heaven say: “Now have come the salvation and the power and the kingdom of our God, and the authority of his Messiah. For the accuser of our brothers and sisters, who accuses them before our God day and night, has been hurled down.
He is our Advocate and Atoning Sacrifice:
When we sin, Christ declares to the Father our righteous standing because of His sacrifice and our faith in Him.
1 John 2:1-2 NIV
My dear children, I write this to you so that you will not sin. But if anybody does sin, we have an advocate with the Father---Jesus Christ, the Righteous One.  He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.
He is the Mediator of the New Covenant:
Hebrews 9:15 NIV
For this reason Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance---now that he has died as a ransom to set them free from the sins committed under the first covenant.
He is justifying and declaring repenting unbelievers righteous:
Romans 4:5 NIV
However, to the one who does not work but trusts God who justifies the ungodly, their faith is credited as righteousness.
He is our great High Priest:
Hebrews 4:14 NIV
Therefore, since we have a great high priest who has ascended into heaven, Jesus the Son of God, let us hold firmly to the faith we profess.
He is receiving those that the Father gives Him:
John 6:37 (NIV)
37 All that the Father gives me will come to me, and whoever comes to me I will never drive away.
He is providing Mercy and Grace:
Ephesians 4:7 KJV
But unto every one of us is given grace according to the measure of the gift of Christ.
Hebrews 4:16 NIV
Let us then approach God’s throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.
He is actively sitting at the right hand of the Father;
Hebrews 8:1 NIV
Now the main point of what we are saying is this: We do have such a high priest, who sat down at the right hand of the throne of the Majesty in heaven,
He is residing in us in the Person of the Holy Spirit:
Romans 8:10 NIV
But if Christ is in you, then even though your body is subject to death because of sin, the Spirit gives life because of righteousness.
Colossians 1:27 (NIV)
27 To them God has chosen to make known among the Gentiles the glorious riches of this mystery, which is Christ in you, the hope of glory.
He is sealing believers with the promised Holy Spirit:
Ephesians 1:13, 14 NCV
13 So it is with you. When you heard the true teaching—the Good News about your salvation—you believed in Christ. And in Christ, God put his special mark of ownership on you by giving you the Holy Spirit that he had promised. 14 That Holy Spirit is the guarantee that we will receive what God promised for his people until God gives full freedom to those who are his—to bring praise to God’s glory.
He is preparing a place for us:
John 14:2 NIV
My Father’s house has many rooms; if that were not so, would I have told you that I am going there to prepare a place for you....
He is preparing to return to receive His children:
John 14:3 NIV
And if I go and prepare a place for you, I will come back and take you to be with me that you also may be where I am.
He is forgiving the sins of unbelievers when they confess and repent:
1 John 1:9 NIV
If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
As head if His Church, He is directing the affairs of the Church:
(He is constantly connected to His body parts - you and me)
Ephesians 5:23 NIV
For the husband is the head of the wife as Christ is the head of the church, his body, of which he is the Savior.
He is bestowing Spiritual Gifts upon the Church to prepare His people for works of service to build up His Kingdom:
Ephesians 4:11-13 NIV
So Christ himself gave the apostles, the prophets, the evangelists, the pastors and teachers,  to equip his people for works of service, so that the body of Christ may be built up  until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ.
1 Corinthians 12:4-11 NIV
There are different kinds of gifts, but the same Spirit distributes them.  There are different kinds of service, but the same Lord.  There are different kinds of working, but in all of them and in everyone it is the same God at work.  Now to each one the manifestation of the Spirit is given for the common good.  To one there is given through the Spirit a message of wisdom, to another a message of knowledge by means of the same Spirit,  to another faith by the same Spirit, to another gifts of healing by that one Spirit,  to another miraculous powers, to another prophecy, to another distinguishing between spirits, to another speaking in different kinds of tongues, and to still another the interpretation of tongues.  All these are the work of one and the same Spirit, and he distributes them to each one, just as he determines.
He is protecting His Church:
Matthew 16:18 KJV
And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
He is listening to and answering our prayers:
2 Corinthians 12:8-9 (NIV)
8 Three times I pleaded with the Lord to take it away from me. 9 But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly about my weaknesses, so that Christ's power may rest on me.
He is perfecting our faith:
Hebrews 12:2 (NIV)
2 Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God.
He is giving us rest from trying to earn our way to heaven through law keeping, etc.
Matthew 11:28-30 KJV
Come unto me, all ye that labour and are heavy laden, and I will give you rest.  Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls.  For my yoke is easy, and my burden is light.
He is our Shepherd:
The 23rd Psalm speaks of the Good Shepherd and the age of grace. God wants to bless us to the point that our “cup runneth over” and “His goodness and mercy follow us all the days of our lives.” We are living right now in Psalm 23 and its promises belong to us. The Good Shepherd leads us, guides us, protects us, and we “shall not want” for anything as we abide under His care.
Knowing what Jesus is currently doing in the heavenly sanctuary rids me of the fear and uncertainly that I once felt and now I am confident in knowing that He will allow nothing to snatch me out of His hand.
John 10:27-29 (KJV)
27 My sheep hear my voice, and I know them, and they follow me:
28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.
I hope this has been helpful. Blessings always.