Richard Rohr’s personal justification for adopting the practice of the Enneagram is twofold.
First, he argues that “in principle, the whole world and everything it that is good, true, and beautiful is at the disposal of Christians: ‘For all things are yours… and your are Christ’s.’” The context of this verse is making an argument agains the world’s wisdom.
1 Corinthians 3:18-23 Do not deceive yourselves. If any of you think you are wise by the standards of this age, you should become “fools” so that you may become wise. 19 For the wisdom of this world is foolishness in God’s sight. As it is written: “He catches the wise in their craftiness” [Job 5:13]; 20 and again, “The Lord knows that the thoughts of the wise are futile.” [Psalm 94:11] 21 So then, no more boasting about human leaders! All things are yours, 22 whether Paul or Apollos or Cephas [that is, Peter] or the world or life or death or the present or the future—all are yours, 23 and you are of Christ, and Christ is of God.
By contrasting the two “wisdoms”; the wisdom of God and the world’s wisdom, Paul means that to become truely wise you must become a fool according to the world. Therefore, to boast about human leaders [and the wisdom they teach] is foolishness, for the true source of wisdom is God and cannot be contained by any mere human (v. 4) of his personal teaching. Establishing this as the contexts shows that the “all things” Paul is referring to is all the spiritual blessings of the gospel. There are no superior groups, with a greater revelation. Christ is the foundation from the start (v. 11), he is the one growing the church (v. 6-7), and if you are in Christ already you have it all. There is no secret wisdom available to some that you don’t already possess.
Instead of providing a justification for the teaching of the Enneagram, 1 Corinthians is actually making an argument against it. The Enneagram establishes a class of people with access to a greater source of spiritual blessing than the average Christian. This makes it a form of worldly wisdom that God calls foolishness (v. 19).
Second, he mentions that “Paul himself and John the Evangelist have taken over and ‘baptised’ ideas and images form both Greek philosophy of religion of their own day.”  This justification equivocates between Paul and John’s use of terms the Greeks employed, with the rituals and practices the Greek used as a part of their practice for sanctification. Moreover, their employment of Greek terminology is not used in the same way that the Greeks used their terminology, but rather in the sense commensurate with the Jewish Old Testament. For instance, “Logos” (John 1:1-3, 14) was not used in the Stoic or Platonist sense of Hellenistic philosophy, as an impersonal force underlying all reality, but in the Jewish sense, as the wisdom of a personal creator of all things, exerting his sovereign will over human history. Rather than reason from similarities from ancient wisdom, the Enneagram does the opposite: it tries to fit Christian principles into ancient wisdom. The mindset begins with pagan philosophy and recasts Christian principles into that mould, rather than beginning with a mindset formed from the mould of Scripture’s revelation and using the terms and ideas of Pagan wisdom to explain it.
In conclusion, both of Rohr’s justifications for adopting the practice of the Enneagram are fraught with error. It is not wise to trust someone who twists the teaching of Scripture to say the opposite of what it teaches and stroke his own pet philosophy. Thinking himself wise he has become a fool (1 Corinthians 3:18). It is the folly of this age and not the wisdom of the next, where Christ is all we need.
 Rohr and Ebert, The Enneagram: A Christian Perspective, Kindle 155.
For other posts on the Enneagram;
The above critique relied heavily upon the work of Dr. Christopher Berg, and his excellent book on the topic, The Trojan Horse: What Christians should know about Yoga and the Enneagram.