John Gill Commentary 1 Chronicles 28:10

"Take heed now; for Jehovah hath chosen thee to build a house for the sanctuary: be strong, and do it." — 1 Chronicles 28:10 (ASV)

Take heed now
Of offending God by forsaking him; or see, consider, and observe now what he was further about to say to him, concerning the building of the temple, as follows:

for the Lord has chosen you to build an house for the sanctuary ;
a temple for the ark, called the sanctuary, (Numbers 7:9) (10:21) the Targum is, the Word of the Lord has chosen you

be strong, and do it ,
be of a good heart and courage, and set about it with vigour and resolution.