Verse 12, "Therefore said I, The Philistines will come down now upon me to Gilgal, and I have not made supplication unto the LORD: I forced myself therefore, and offered a burnt offering."
King Saul got impatient and decided to do the job of Samuel for him. The offering of the sacrifice was Samuel's responsibility. Saul knew Samuel was coming but he was unwilling to wait for him to arrive. We could say that Saul got ahead of God's timing.
It can be very difficult in life to wait on God's perfect timing. We are much better off continuing to pray for his leading than we are trying to manufacture what we are asking God to do. His when and how will always work out much better than we could ever imagine.