NET

51 He gives his king magnificent victories; he is faithful to his chosen ruler, to David and to his descendants forever!”

Darby

51 [It is he] who giveth great deliverances to^D2049 his king, And sheweth loving-kindness to his anointed, To David, and to his seed for evermore.

Darby Bible Notes

to - Some read 'He is a tower of deliverance for.'

KJV

51 [He is] the tower of salvation for his king: and sheweth mercy to his anointed, unto David, and to his seed for evermore.

Strong's

51 He is] is the tower^{H4024 H1431} of salvation^H3444 for his king^H4428: and sheweth^H6213 mercy^H2617 to his anointed^H4899, unto David^H1732, and to his seed^H2233 for^H5704 evermore^H5769.