Jamieson, Fausset and Brown on Mark 6:45

45. And straightway he constrained his disciples to get into the ship, and to go to the other side before--Him.

unto Bethsaida--Bethsaida of Galilee (Joh 12:21). John (Joh 6:17) says they "went over the sea towards Capernaum"--the wind, probably, occasioning this slight deviation from the direction of Bethsaida.

while he sent away the people--"the multitude." His object in this was to put an end to the misdirected excitement in His favor (Joh 6:15), into which the disciples themselves may have been somewhat drawn. The word "constrained" implies reluctance on their part, perhaps from unwillingness to part with their Master and embark at night, leaving Him alone on the mountain.