Es irrt der Mensch, solang er strebt bedeutung

„All men are liable to err.But when an error is made, that man is no longerunwise or unblessed who heals the evil

into which he has fallen and does not remain stubborn.“

—  Sophocles ancient Greek tragedian -496 - -406 BC

τοῖς πᾶσι κοινόν ἐστι τοὐξαμαρτάνειν:ἐπεὶ δ᾽ ἁμάρτῃ, κεῖνος οὐκέτ᾽ ἔστ᾽ ἀνὴρἄβουλος οὐδ᾽ ἄνολβος, ὅστις ἐς κακὸνπεσὼν ἀκῆται μηδ᾽ ἀκίνητος πέλῃ. Original: (el) τοῖς πᾶσι κοινόν ἐστι τοὐξαμαρτάνειν: <br/> ἐπεὶ δ᾽ ἁμάρτῃ, κεῖνος οὐκέτ᾽ ἔστ᾽ ἀνὴρ <br/> ἄβουλος οὐδ᾽ ἄνολβος, ὅστις ἐς κακὸν <br/> πεσὼν ἀκῆται μηδ᾽ ἀκίνητος πέλῃ.

Source: Antigone, Lines 1024-1027; cf. Book of Proverbs 28:13

„Man is a goal-seeking animal. His life only has meaning if he is reaching out and striving for goals.“

—  Aristotle Classical Greek philosopher, student of Plato and founder of Western philosophy -384 - -321 BC

Attributed to Aristotle in Bernhoff A. Dahl, Optimize Your Life! http://books.google.gr/books?id=B1Z2XP_DamQC&dq=, Trionics International Inc., 2005, p. 111.
Disputed

„The wise man will live as long as he ought, not as long as he can.“
Sapiens vivit quantum debet, non quantum potest.

—  Seneca the Younger Roman Stoic philosopher, statesman, and dramatist -4 - 65 BC

Source: Epistulae Morales ad Lucilium (Moral Letters to Lucilius), Letter LXX: On the proper time to slip the cable, Line 4.

„And striving to be man, the worm
Mounts through all the spires of form.“

—  Ralph Waldo Emerson American philosopher, essayist, and poet 1803 - 1882

May-Day
Bartlett's Familiar Quotations, 10th ed. (1919)

„Man as man can never know God: His wishing, seeking, and striving are all in vain.“

—  Karl Barth Swiss Protestant theologian 1886 - 1968

In "Karl Barth's Conception of God" (1952) http://mlk-kpp01.stanford.edu/primarydocuments/Vol2/520102BarthsConceptionOfGod.pdf by Martin Luther King, Jr., King cites this as a statement of Barth's in The Epistle to the Romans, p. 91, but it does not actually appear in the 1933 translation of Edwin Hoskyns. It may be a paraphrase of some of Barth's ideas which were incorrectly cited.
Disputed

„Because I do not hope to turn againBecause I do not hopeBecause I do not hope to turnDesiring this man's gift and that man's scope

I no longer strive to strive towards such things“

—  T.S. Eliot 20th century English author 1888 - 1965

Ash-Wednesday (1930) Context: Because I do not hope to turn againBecause I do not hopeBecause I do not hope to turnDesiring this man's gift and that man's scopeI no longer strive to strive towards such things(Why should the agèd eagle stretch its wings?)Why should I mourn

The vanished power of the usual reign?

„By striving to do the impossible, man has always achieved what is possible.“

—  Mikhail Bakunin Russian revolutionary, philosopher, and theorist of collectivist anarchism 1814 - 1876

Attributed to Bakunin in The Explorers (1996) by Paolo Novaresio
Context: By striving to do the impossible, man has always achieved what is possible. Those who have cautiously done no more than they believed possible have never taken a single step forward.