“Come away by yourselves to a deserted place and rest a while.” (Mark 6:31)

Jesus did not only ask his disciples to take a good rest, but to also share the experience from their missionary work.

From the Gospel of Luke, we can see when the disciples were sharing their experience, Jesus also taught them at the same time.
“The seventy two returned rejoicing, and said, “Lord, even the demons are subject to us because of your name.” Jesus said, “I have observed Satan fall like lightning from the sky. Behold, I have given you the power 'to tread upon serpents' and scorpions and upon the full force of the enemy and nothing will harm you. Nevertheless, do not rejoice because the spirits are subject to you, but rejoice because your names are written in heaven.”” (Luke 10:17-20)

“Go to the wilderness and rest” was Jesus’ habit. Only in the quietness, the heart will find it easier to converge and pray.

Before the selection of the twelve disciples, “Jesus departed to the mountain to pray, and he spent the night in prayer to God. When day came, he called his disciples to himself, and from them he chose Twelve, whom he also named apostles.” (Luke 6:12-13)

After finishing the Passover dinner, “Then going out he went, as was his custom, to the Mount of Olives, and the disciples followed him. When he arrived at the place he said to them, “Pray that you may not undergo the test.”” (Luke 22:29-40)

If we do not have the time and space to be quiet, then it would be almost impossible to pray with the heart.