“And the apostles gathered themselves together unto Jesus, and told him all things, both what they had done, and what they had taught.”
Mark 6:30 — Greek Interlinear
Church Fathers on Mark 6:30
For they return to the fountain-head whence the streams flow; those who are sent by God, always offer up thanks for those things which they have received.
Let us also learn, when we are sent on any mission, not to go far away, and not to overstep the bounds of the office committed, but to go often to him, who sends us, and report all that we have done and taught; for we must not only teach but act.
Not only do the Apostles tell the Lord what they themselves had done and taught, but also His own and John’s disciples together tell Him what John had suffered, during the time that they were occupied in teaching, as Matthew relates.