Translating: "Know and understand this king. Be sure that you make yourself a disciple of Christ the ruling King."

Question

I am trying to write a motto and my knowledge of Latin is not very profound.

I wish to state using Latin to the effect of, and using king rather than man:

Know and understand this king. Be sure that you make yourself a disciple of Christ the ruling King.

To know and understand is suggested to be as grok. I do not wish to over complicate.

The best arrangement that I have so far come up with is,

Intellegere et scire regem. Fac tu discipulis Christi Regis

Is this anything near close? What would be correct Latin?

I do hope that this question will be allowed.

Edit

Having studied the magnificent answer from Ethan Bierlein and elsewhere I have near settled that the motto will be as follows:

Scītō atque intellege hunc rēgem. Es certus facere tē discipulum Christī Regēntis.

Answers yet improving upon this will be considered.

Answer 1

The first sentence in your translation is somewhat on-track, you simply neglected to insert the first person demonstrative adjective (hic, haec, hoc) for rēgem and used infinitive forms instead of imperative forms. The second sentence, however, is not terribly on-track (i.e, improper use of an imperative, incorrect indirect discourse, an incorrectly declined noun, etc.).

If you care less for a more pragmatic translation, I might suggest the following two sentences. If you are addressing a singular person:

Scītō atque intellege hunc rēgem. Es certus facere tē discipulum Christī, regentis rēgis.

If you are addressing a singular person, and that person is female, then certus and discipulum should become certa and discipulam, respectively.

If you are addressing multiple people.

Scītōte atque intellegite hunc rēgem. Este certī facere vōs discipulōs Christī, regentis rēgis.

If you mistyped in your original question, and meant to type "know and understand this, king" instead of "know and understand this king", then rēgem should be in its vocative form, rēx. A feminine or plural sentence would then be unnecessary, thus making your full sentence:

Scītō atque intellege hoc, rēx. Es certus facere tē discipulum Christī, regentis rēgis.

Answer 2

For the opening words a C10 hagiography copied into Harley 2253 f132v ch.5 keeps "Rex" in the nominative/vocative, which seems better than regem, Accusative:
"King, recognise and understand:"

Rex accippe et intellige

and the King is promised a throne at the heavenly banquet.