Romans 5 has NOTHING to do with Piper's view. NOTHING. Let's look at Piper, the seasoned pastor, teacher, and Tweeter:
"Muslims, Jews, Christians! Allah and Adonai are only known and loved through the crucified and risen Christ. John 8:19; 5:42-43"
Allah AND Adonai
the crucified and risen CHRIST.
Now, looking at it word for word you can see enormous doctrinal error.
Muslims worship Allah, a demon moon god, and think some "good" (5 pillars of Islam, jihad, honor killings) works will get them to "Paradise". They worship (for all intents and purposes) Muhammad. The quran, a demonic book, is nothing but lies.
Jews rely on bloodline and tradition, and rely on other works in addition to these, to save them.
Christians--now BIBLICAL Christians rely solely on the finished work of the risen Lord Jesus Christ, who is God, Creator, Second person in the Trinity, sole Messiah and Master and Owner: THE Way, THE Truth, and THE Life.
I'll state here, knowing Piper's penchant for Roman Catholic authors and practices like Lectio Divina, that Roman Catholics aren't Christians. They too, rely on works and tradition and have a false God altogether.
Jews, Muslims, and Catholics are all equally lost because all three reject the God of Scripture and the sole way of eternal life and forgiveness of sin, which is Jesus Christ and His FINISHED work at the Cross.
By typing "Allah and Adonai", Piper puts Allah, the demon of Islam, on par with Adonai, that is, the HOLY HOLY HOLY One of Israel. Allah is a creation, Jehovah is eternal.
"can only" = no other way
"be known" = to be no stranger to, to be familiar with
"loved" = embraced, have affection for, to be pleased with, have high regard for
"through" = the means of, transmission
"the crucified and risen Christ" = the Jesus of Scripture is the crucified and risen Lord.
So BOTH Allah and Adonai/Jehovah can ONLY be known and loved through Jesus Christ? This statement is blatantly false for two reasons:
We are to love God alone (see Ex. 20).
Allah is a demon who is NOT trinitarian but Adonai is; he is "the greatest of deceivers" according to the quran; the Triune God of Scripture cannot lie, but rather is the God of Truth; he is not holy but Adonai is; he is not immutable, but Adonai is; he has no son, but Adonai does--Jesus Christ (the Trinity cannot be chopped up: One God, three distinct persons in the Godhead, each co-equally God with all the attributes, and all three make the ONE GOD); Allah is not Creator, but Adonai is; Allah commanded Satan to worship Adam but Adonai prohibits all worship of anyone other than HIMSELF.
Allah therefore cannot only NOT be known nor love through Christ, it is Christ Jesus who created Allah (the demon) and it is Christ Jesus who will throw Allah into Lake of Fire to burn for eternity. Allah is not to be "known" but rejected; he is not to be loved (how utterly UNHOLY the "love" Piper portrays, is!) but hated.
Ironically, instead of knowing the demon of Allah and loving him through Christ:
Col 2:15 When He had disarmed the rulers and authorities, He made a public display of them, having triumphed over them through Him.
Rom 16:17 Now I urge you, brethren, keep your eye on those who cause dissensions and hindrances contrary to the teaching which you learned, and turn away from them.
Rom 16:18 For such men are slaves, not of our Lord Christ but of their own appetites; and by their smooth and flattering speech they deceive the hearts of the unsuspecting.
Rom 16:19 For the report of your obedience has reached to all; therefore I am rejoicing over you, but I want you to be wise in what is good and innocent in what is evil.
Rom 16:20 The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you.
Piper is not a novice in theology, religion, or Tweeting. He was deliberate and again, defiant, unapologetic and sees himself having to answer to no one who asked perfectly biblical questions for his atrocious claims.
For more info on the name of Allah and how it is NOT the name of the triune God of Scripture go to Let Us Reason.
Recently heretic Steve Chalke said this:
“Ultimately the full interpretation of who Allah/God is can be seen through Jesus”.
Pretty much the same thing as false teacher John Piper.