Long time therefore abode they speaking boldly in the Lord, which gave testimony unto the word of his grace, and granted signs and wonders to be done by their hands. Long time therefore abode they - Because they had great success, therefore they continued a long time, gaining many converts, and building up those who had believed, in their most holy faith; notwithstanding the opposition they met with, both from the unbelieving Jews and heathens.
Speaking boldly - Παρῥησιαζομενοι, Having great liberty of speech, a copious and commanding eloquence, springing from a consciousness of the truth which they preached.
The word of his grace - The Gospel of Jesus Christ, which is the doctrine of God's grace, mercy, or favor to mankind.
And granted signs and wonders to be done - For no apostle could work a miracle by himself; nor was any sign or wonder wrought even by the greatest apostle, but by an especial grant or dispensation of God. This power was not resident in them at all times; it was only now and then communicated, when a miracle was necessary for the confirmation of the truth preached.