"How do you know that He will be there with you tomorrow, the next day, etc."
The fact is that I struggle with fights in my mind all the time.
I was convinced that I had to hold onto His presence in my life based on what I was feeling.
I knew that I was made the righteousness of God in Christ, but I still thought that I had to bring Him into my life, that His presence in my life depended on me.
For a long time afterward, I was till convinced that His life and power depended on what I was thinking and feeling. Such bondage.
What changed that wrong thinking and believing?
I had a revelation of Jesus as my Shepherd:
"A Psalm of David.} The LORD is my shepherd; I shall not want." (Psalm 23)
Notice that David writes "The LORD" -- the Covenant Name of God:
"And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you." (Exodus 3: 14)
Today, I have the revelation of all that God is through His Son Jesus:
"Jesus Christ the same yesterday, and to day, and for ever." (Hebrews 13: 8)
The further revelation of how present God is to us, we find in Psalm 137:
"2Thou knowest my downsitting and mine uprising, thou understandest my thought afar off.
3Thou compassest my path and my lying down, and art acquainted with all my ways." (Psalm 139: 2-3)
"8If I ascend up into heaven, thou art there: if I make my bed in hell, behold, thou art there.
"9If I take the wings of the morning, and dwell in the uttermost parts of the sea;
"10Even there shall thy hand lead me, and thy right hand shall hold me." (Psalm 139: 8-10)
Even if we try to flee God's presence, we cannot!
"7Whither shall I go from thy spirit? or whither shall I flee from thy presence?" (Psalm 139: 7)
He will never leave me nor forsake me. His presence, His blessings, His work in my life, in our lives, do not depend on us.
It all has come about because of Jesus!
So, whenever the question, the attack pops up to answer the question: "What are you going to do to make sure that He is there in your tomorrows?"
I answer with the Word of God, which announces at length that He is already in my tomorrows, and holds all of eternity in His hands.