Read the Bible, and you'll conclude that the best of God's people are jacked up. Any cursory survey of the lives of God’s messengers and ministers confirms that the answer to the rhetorical question “who is sufficient for these things,” is in fact “no one” (2 Cor.2:16). We find multiple blights and blemishes in the very people presented as paradigms.
Abraham, the father of faith, has his bouts with fear and faithlessness (e.g. Gen.20). Isaac is a spitting image of his daddy by buckling under the same temptation (Gen.26). Jacob deceives and manipulates to possess God’s promises. Moses strikes when he should speak. David embodies the ethos of worship on the one hand, but then manipulates, lies, kills, and covers up on the other. Solomon waxes in righteousness in the first part of his ministry, and wanes in idolatry in the later part. Elijah surges with faith before the prophets of Baal and Ashtoreth, only to dwindle into despair with the threats of Jezebel. The apostles are seen foolishly jockeying for positions of power as Jesus walks the path to Golgotha. The disciples are repeatedly labeled as faithless and hard of heart. Peter denies Christ when pressured by the Jews. After the advent of the Holy Spirit, Peter compromises the message of the gospel when pressured by… the Jews. John Mark defects. Paul discloses the chasmic gulf between his desires and his faith.
All this to say, the biographies of great men of God remind us that they are no less in need of the pure and perfect righteousness of Christ than anyone else.