John Gill Commentary Matthew 20:5

"Again he went out about the sixth and the ninth hour, and did likewise." — Matthew 20:5 (ASV)

Again he went out about the sixth and ninth hour
About twelve o'clock, or at noon, and three o'clock in the afternoon. These three last mentioned seasons of the day, were the hours of prayer; see (Acts 2:15) (3:1) (10:9) and did likewise: seeing others in the same place, and posture, he called them, and sent them into his vineyard, to labour there, giving them the same promise he did to others.