“I am grieved that I have made Saul King,because he has turned away from me and has not carried out my instructions” I Sam 15:11.
The word grieve literally means God "was sorry". He regrets and he also regrets in Genesis 6:6 “The Lord was grieved that he had made man on the earth ,and his heart was filled with pain.”
In both the cases it is people who have changed not God.
Saul was anointed as the head of the tribes of Israel by the Lord. But Saul did not obey God .God is the one who is knowing all definitely knows Saul's mind but He wanted to give him a chance to Saul to prove himself as a faithful and an obedient servant since he had exalted him to the highest position. But Saul did not obey God he takes his own decision neglecting God's Voice.
Lord spoke through Samuel the prophet very clearly that he should destroy everything that belongs to Amalekites(I Sam 15:3).But Saul and the army spared Agag and the best of the sheep and cattle and everything that was good to sacrifice to the Lord and they didnt destroy completely. So the Lord was grieved and Saul was rejected by the Lord as the King of Israelites. To obey is better than sacrifice.In Hos 6:6 it says “For I desire mercy, not sacrifice, and acknowledgment of God rather than burnt offerings”.To love him with all your heart...(Mark 12:33) is more important than any other sacrifices that we are doing. If God states his desire clearly why did the Israelites and why do we have such difficulty in following it?
God the Father clearly states what he wants from us in our hearts.we can play in all religious activities,we may attend church services regularly or even we may be doing the ministry of God but if we are not obeying God's word and listen to his voice everything will go in vain and we would be the reason for the recede. Our Lord GOD delights in obeying his voice.
The Lord expected the same obedience from Adam and Eve, and Moses because He exalted them in a high place and had blessed them. But all these people failed to obey the Voice of God and figured out their own way and ran into the consequences.
So Friends GOD needs you not to lie or change your mind because he doesn't not need a man who changes his mind frequently. Learn to listen to the Voice of God and ask for the guidance of the Holy spirit and he will teach you to follow his ways. Our priority in life should be to keep his words in mind and follow all his decrees without giving any false reasons looking at the circumstances.