You must be referring to Psalm 37:25, "I have been young and now I am old, Yet I have not seen the righteous forsaken Or his descendants begging bread"; here David stated that in all his years he had never witnessed the Lord forsaking His children. This is a theme through out scripture, God's everlasting faithfulness to His children:
Ps 94:14, For the LORD will not abandon His people, Nor will He forsake His inheritance.
1 Sa 12:22, For the LORD will not abandon His people on account of His great name. . .
Heb 13:5, . . .for He Himself has said, ? I WILL NEVER DESERT YOU, NOR WILL I EVER FORSAKE YOU,?