Matthew 6:25

διὰ τοῦτο, i.e. because this double service is impossible there must be no distraction of thought.

μὴ μεριμνᾶτε. ‘Do not be anxious,’ which was the meaning of ‘take no thought,’ when the E. V. was made. The same word occurs Philippians 4:6, μηδὲν μεριμνᾶτε, where, as here, the tense marks continuance, ‘do not be ever anxious.’ Cp. 1 Peter 5:7, πᾶσαν τὴν μέριμναν ὑμῶν ἐπιρίψαντες ἐπʼ αὐτόν. See Bp Lightfoot, On a Fresh Revision of the New Testament, &c., p. 171.

The argument in the verse is: such anxiety is unnecessary; God gave the life and the body; will He not give the smaller gifts of food and clothing?
Socrates describes this to be the object of his mission: ‘to persuade young and old,’ μήτε σωμάτων ἐπιμελεῖσθαι μήτε χρημάτων πρότερον μηδὲ οὕτω σφόδρα ὡς τῆς ψυχῆς ὅπως ὡς�. See Matthew 6:34 for a continuation of this quotation.