Gregory the Great — on 1Sam 2:4 (Commentary on 1 Kings, Book 1, Chapter 3)

“Indeed, by the name of strength, the power of the Holy Spirit is shown. Hence the Lord, promising this same Spirit to the disciples, says: 'But remain in the city until you are clothed with power from on high' (Luke 24:49). And the grace of the Holy Spirit is rightly called strength, because when the elect receive it, they become strong against all adversities of this world. But who are the weak in this place to be understood as, if not the apostles? But they were certainly weak when the bow of the mighty was bent, not when they were clothed with power from on high. For in the hour of the Lord's arrest it is written of them that, 'leaving the Lord, they all fled' (Matthew 26:56). Was not Peter very weak then, when he feared the voice of a questioning servant girl and denied the Redeemer (Matthew 26:63, 74)? Already indeed the bow of the mighty had been overcome, the savagery of the Jews brought to nothing, because the Redeemer had risen after conquering death; and yet still the weak apostles feared the overcome mighty ones behind closed doors (John 20:19). But where strength clothed them, it is fitting to observe how strong it made them. For the Holy Spirit came upon them with a sudden sound, and changed their weakness into the power of wonderful love (Acts 2:2ff.). For they began to preach Christ, now clothed with strength, who had not been ashamed to flee and hide from the threats of persecutors; and those who had feared the words of women broke the authority of rulers with freedom. Strength conquered fear, overcame terrors, threats, and slaughter; and those whom it clothed by coming upon them, it adorned with the insignia of marvelous boldness in the heavenly warfare, so that amid scourges, slaughter, and reproaches they did not fear, but rejoiced. For it is written of them now clothed with this strength: 'The apostles went from the presence of the council rejoicing, because they were counted worthy to suffer disgrace for the name of Jesus' (Acts 5:41). Hence now preaching, they say: 'Count it all joy, brothers, when you fall into various trials' (James 1:2). Well therefore it is said: 'The bow of the mighty is overcome, and the weak are girded with strength.' Because first the Redeemer rose from the dead, and thus went to heaven, and sent the Holy Spirit to the disciples. For first the bow of the mighty had to be overcome, and afterward the weak were to be girded with strength. Hence it is also written: 'The Spirit had not yet been given, because Jesus had not yet been glorified' (John 7:39).”