Bede

And there were with him about four hundred men. Those who remain firm in faith, acting manfully and strengthened in heart by the doctrine of the Gospel, which is marked by the most beautiful unity of the four books, are called to hope for, seek, and obtain the heavenly kingdoms. For the number one hundred, which, after so many numbers running on the left, first seeks the right hand, as has been often said, reveals the entrance of the higher kingdom once the lower labors are completed. …

Commentary on Samuel ↗