For You are my hope, O Lord GOD; You are my trust from my youth.
Psalm 71:5 (NKJV)
For thou art my hope, O Lord God – The basis for my hope and my expectations are in you.
Thou art my trust from my youth – From my earliest years.
Meaning that he had always trusted in God and had always found him a helper. All that he was and all that he possessed, he owed to God and he felt now that God had been his protector from his earliest years.
Perhaps it cannot be shown that he meant to say that he had actually trusted in God from his youth, for the language means no more than that God had protected him and held him up, and had continually intervened to save and keep him.
As God had always been his Protector, he felt that he might come to Him now and put his trust in Him.